Find a sequence of 7 consecutive primes
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2
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Find a sequence of 7 consecutive primes, such that these primes have to have the same "gap" in between them. So far I have been doing this in a brute force way, by looking at a list of all the primes and trying different combinations without much luck. Is there a more sophisticated way of doing this?
number-theory prime-numbers
|
show 4 more comments
up vote
2
down vote
favorite
Find a sequence of 7 consecutive primes, such that these primes have to have the same "gap" in between them. So far I have been doing this in a brute force way, by looking at a list of all the primes and trying different combinations without much luck. Is there a more sophisticated way of doing this?
number-theory prime-numbers
3
Note that the common difference will have to be divisible by $2times 3times 5times 7=210$ in order to avoid divisibility by $2,3,5,7$.
– Mark Bennet
Nov 11 '14 at 18:39
1
First, start simple: can you see why a gap of $2$ between primes won't work? Once you see that, you can ask yourself why a gap of $6=2cdot 3$ won't work, and by continuing in this approach you should be able to find the minimum gap that you can use.
– Steven Stadnicki
Nov 11 '14 at 18:40
1
You can look up examples.
– Henning Makholm
Nov 11 '14 at 18:42
2
And this usenet post claims that the smallest known (as of 10 years ago) example is $149143516628800164802930723713131 + 210n$.
– Henning Makholm
Nov 11 '14 at 18:46
1
@DietrichBurde: Those may be primes, but they are not consecutive primes.
– Henning Makholm
Nov 11 '14 at 18:46
|
show 4 more comments
up vote
2
down vote
favorite
up vote
2
down vote
favorite
Find a sequence of 7 consecutive primes, such that these primes have to have the same "gap" in between them. So far I have been doing this in a brute force way, by looking at a list of all the primes and trying different combinations without much luck. Is there a more sophisticated way of doing this?
number-theory prime-numbers
Find a sequence of 7 consecutive primes, such that these primes have to have the same "gap" in between them. So far I have been doing this in a brute force way, by looking at a list of all the primes and trying different combinations without much luck. Is there a more sophisticated way of doing this?
number-theory prime-numbers
number-theory prime-numbers
edited Nov 21 at 15:02
Klangen
1,32811130
1,32811130
asked Nov 11 '14 at 18:35
Math Major
1,06021437
1,06021437
3
Note that the common difference will have to be divisible by $2times 3times 5times 7=210$ in order to avoid divisibility by $2,3,5,7$.
– Mark Bennet
Nov 11 '14 at 18:39
1
First, start simple: can you see why a gap of $2$ between primes won't work? Once you see that, you can ask yourself why a gap of $6=2cdot 3$ won't work, and by continuing in this approach you should be able to find the minimum gap that you can use.
– Steven Stadnicki
Nov 11 '14 at 18:40
1
You can look up examples.
– Henning Makholm
Nov 11 '14 at 18:42
2
And this usenet post claims that the smallest known (as of 10 years ago) example is $149143516628800164802930723713131 + 210n$.
– Henning Makholm
Nov 11 '14 at 18:46
1
@DietrichBurde: Those may be primes, but they are not consecutive primes.
– Henning Makholm
Nov 11 '14 at 18:46
|
show 4 more comments
3
Note that the common difference will have to be divisible by $2times 3times 5times 7=210$ in order to avoid divisibility by $2,3,5,7$.
– Mark Bennet
Nov 11 '14 at 18:39
1
First, start simple: can you see why a gap of $2$ between primes won't work? Once you see that, you can ask yourself why a gap of $6=2cdot 3$ won't work, and by continuing in this approach you should be able to find the minimum gap that you can use.
– Steven Stadnicki
Nov 11 '14 at 18:40
1
You can look up examples.
– Henning Makholm
Nov 11 '14 at 18:42
2
And this usenet post claims that the smallest known (as of 10 years ago) example is $149143516628800164802930723713131 + 210n$.
– Henning Makholm
Nov 11 '14 at 18:46
1
@DietrichBurde: Those may be primes, but they are not consecutive primes.
– Henning Makholm
Nov 11 '14 at 18:46
3
3
Note that the common difference will have to be divisible by $2times 3times 5times 7=210$ in order to avoid divisibility by $2,3,5,7$.
– Mark Bennet
Nov 11 '14 at 18:39
Note that the common difference will have to be divisible by $2times 3times 5times 7=210$ in order to avoid divisibility by $2,3,5,7$.
– Mark Bennet
Nov 11 '14 at 18:39
1
1
First, start simple: can you see why a gap of $2$ between primes won't work? Once you see that, you can ask yourself why a gap of $6=2cdot 3$ won't work, and by continuing in this approach you should be able to find the minimum gap that you can use.
– Steven Stadnicki
Nov 11 '14 at 18:40
First, start simple: can you see why a gap of $2$ between primes won't work? Once you see that, you can ask yourself why a gap of $6=2cdot 3$ won't work, and by continuing in this approach you should be able to find the minimum gap that you can use.
– Steven Stadnicki
Nov 11 '14 at 18:40
1
1
You can look up examples.
– Henning Makholm
Nov 11 '14 at 18:42
You can look up examples.
– Henning Makholm
Nov 11 '14 at 18:42
2
2
And this usenet post claims that the smallest known (as of 10 years ago) example is $149143516628800164802930723713131 + 210n$.
– Henning Makholm
Nov 11 '14 at 18:46
And this usenet post claims that the smallest known (as of 10 years ago) example is $149143516628800164802930723713131 + 210n$.
– Henning Makholm
Nov 11 '14 at 18:46
1
1
@DietrichBurde: Those may be primes, but they are not consecutive primes.
– Henning Makholm
Nov 11 '14 at 18:46
@DietrichBurde: Those may be primes, but they are not consecutive primes.
– Henning Makholm
Nov 11 '14 at 18:46
|
show 4 more comments
1 Answer
1
active
oldest
votes
up vote
3
down vote
accepted
http://primerecords.dk/cpap.htm lists largest and smallest known examples of consecutive primes in arithmetic progression of a given length.
The first known sequence is apparently $19252884016114523644357039386451+210n$, but is not known to be the first.
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
1
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
1
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
http://primerecords.dk/cpap.htm lists largest and smallest known examples of consecutive primes in arithmetic progression of a given length.
The first known sequence is apparently $19252884016114523644357039386451+210n$, but is not known to be the first.
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
1
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
1
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
add a comment |
up vote
3
down vote
accepted
http://primerecords.dk/cpap.htm lists largest and smallest known examples of consecutive primes in arithmetic progression of a given length.
The first known sequence is apparently $19252884016114523644357039386451+210n$, but is not known to be the first.
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
1
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
1
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
add a comment |
up vote
3
down vote
accepted
up vote
3
down vote
accepted
http://primerecords.dk/cpap.htm lists largest and smallest known examples of consecutive primes in arithmetic progression of a given length.
The first known sequence is apparently $19252884016114523644357039386451+210n$, but is not known to be the first.
http://primerecords.dk/cpap.htm lists largest and smallest known examples of consecutive primes in arithmetic progression of a given length.
The first known sequence is apparently $19252884016114523644357039386451+210n$, but is not known to be the first.
edited Nov 11 '14 at 19:05
answered Nov 11 '14 at 18:51
Henning Makholm
236k16300534
236k16300534
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
1
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
1
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
add a comment |
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
1
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
1
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
So for simplicity I just want to pick a small one, but I just want to make sure I am reading the chart correctly, so I look at CPAP-k with a k of 7 right? So I chose: 1205967 · 61# + x32a + 210n but I don't understand what the a and # are symbolizing?
– Math Major
Nov 11 '14 at 18:55
1
1
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
@MathMajor: $61#$ is a primorial, that is, the product of all primes up to $61$. And $x_{32a}$ is a particular 32-digit number that is listed further down that page. The smallest known CPAP-7 base is quoted explicitly slightly above the "smallest known CPAP-k" table, after the words "The smallest known is 32 digits".
– Henning Makholm
Nov 11 '14 at 19:02
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
Oh ok, so primorial is like a factorial, but exclusively for the prime numberS?
– Math Major
Nov 11 '14 at 19:04
1
1
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
@MathMajor: Yes.
– Henning Makholm
Nov 11 '14 at 19:05
add a comment |
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3
Note that the common difference will have to be divisible by $2times 3times 5times 7=210$ in order to avoid divisibility by $2,3,5,7$.
– Mark Bennet
Nov 11 '14 at 18:39
1
First, start simple: can you see why a gap of $2$ between primes won't work? Once you see that, you can ask yourself why a gap of $6=2cdot 3$ won't work, and by continuing in this approach you should be able to find the minimum gap that you can use.
– Steven Stadnicki
Nov 11 '14 at 18:40
1
You can look up examples.
– Henning Makholm
Nov 11 '14 at 18:42
2
And this usenet post claims that the smallest known (as of 10 years ago) example is $149143516628800164802930723713131 + 210n$.
– Henning Makholm
Nov 11 '14 at 18:46
1
@DietrichBurde: Those may be primes, but they are not consecutive primes.
– Henning Makholm
Nov 11 '14 at 18:46