(Soft Question) Largest known semiprimes with no known factors












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Is there a list, similar to prime numbers and probable primes, of the largest semiprimes with unknown factors? Is there a list of numbers that are either semiprime or prime, with no known factors? Is there literature on how to find large semi primes?










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  • $begingroup$
    I feel like a list of "possible semiprimes" would likely be at least somewhat coincident with a list of possible primes, given that a large semiprime accordingly has large prime factors (so finding said factors would be difficult, thus rendering the number a possible candidate for either). As for finding large semiprimes, I feel the easiest method would just be to multiply two large known primes together, but I imagine you want something more elegant.
    $endgroup$
    – Eevee Trainer
    Dec 8 '18 at 22:27










  • $begingroup$
    Maybe physics.open.ac.uk/~dbroadhu/cert/semgpch.gp is of interest.
    $endgroup$
    – gammatester
    Dec 8 '18 at 22:34










  • $begingroup$
    It's unclear how one could be certain that a large number was a semiprime (as opposed to having three or more prime factors) without knowing the two prime factors which multiply to it.
    $endgroup$
    – Keith Backman
    Dec 9 '18 at 2:33










  • $begingroup$
    @KeithBackman Surprisingly, this seems to be possible. I heard from a construction of a number which could be proven to be semiprime without known factors (according to the claim, not even by the constructor himself). For huge number, this method is probably not feasible.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:11
















0












$begingroup$


Is there a list, similar to prime numbers and probable primes, of the largest semiprimes with unknown factors? Is there a list of numbers that are either semiprime or prime, with no known factors? Is there literature on how to find large semi primes?










share|cite|improve this question









$endgroup$












  • $begingroup$
    I feel like a list of "possible semiprimes" would likely be at least somewhat coincident with a list of possible primes, given that a large semiprime accordingly has large prime factors (so finding said factors would be difficult, thus rendering the number a possible candidate for either). As for finding large semiprimes, I feel the easiest method would just be to multiply two large known primes together, but I imagine you want something more elegant.
    $endgroup$
    – Eevee Trainer
    Dec 8 '18 at 22:27










  • $begingroup$
    Maybe physics.open.ac.uk/~dbroadhu/cert/semgpch.gp is of interest.
    $endgroup$
    – gammatester
    Dec 8 '18 at 22:34










  • $begingroup$
    It's unclear how one could be certain that a large number was a semiprime (as opposed to having three or more prime factors) without knowing the two prime factors which multiply to it.
    $endgroup$
    – Keith Backman
    Dec 9 '18 at 2:33










  • $begingroup$
    @KeithBackman Surprisingly, this seems to be possible. I heard from a construction of a number which could be proven to be semiprime without known factors (according to the claim, not even by the constructor himself). For huge number, this method is probably not feasible.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:11














0












0








0





$begingroup$


Is there a list, similar to prime numbers and probable primes, of the largest semiprimes with unknown factors? Is there a list of numbers that are either semiprime or prime, with no known factors? Is there literature on how to find large semi primes?










share|cite|improve this question









$endgroup$




Is there a list, similar to prime numbers and probable primes, of the largest semiprimes with unknown factors? Is there a list of numbers that are either semiprime or prime, with no known factors? Is there literature on how to find large semi primes?







reference-request soft-question prime-numbers






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asked Dec 8 '18 at 22:20









Tejas RaoTejas Rao

30611




30611












  • $begingroup$
    I feel like a list of "possible semiprimes" would likely be at least somewhat coincident with a list of possible primes, given that a large semiprime accordingly has large prime factors (so finding said factors would be difficult, thus rendering the number a possible candidate for either). As for finding large semiprimes, I feel the easiest method would just be to multiply two large known primes together, but I imagine you want something more elegant.
    $endgroup$
    – Eevee Trainer
    Dec 8 '18 at 22:27










  • $begingroup$
    Maybe physics.open.ac.uk/~dbroadhu/cert/semgpch.gp is of interest.
    $endgroup$
    – gammatester
    Dec 8 '18 at 22:34










  • $begingroup$
    It's unclear how one could be certain that a large number was a semiprime (as opposed to having three or more prime factors) without knowing the two prime factors which multiply to it.
    $endgroup$
    – Keith Backman
    Dec 9 '18 at 2:33










  • $begingroup$
    @KeithBackman Surprisingly, this seems to be possible. I heard from a construction of a number which could be proven to be semiprime without known factors (according to the claim, not even by the constructor himself). For huge number, this method is probably not feasible.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:11


















  • $begingroup$
    I feel like a list of "possible semiprimes" would likely be at least somewhat coincident with a list of possible primes, given that a large semiprime accordingly has large prime factors (so finding said factors would be difficult, thus rendering the number a possible candidate for either). As for finding large semiprimes, I feel the easiest method would just be to multiply two large known primes together, but I imagine you want something more elegant.
    $endgroup$
    – Eevee Trainer
    Dec 8 '18 at 22:27










  • $begingroup$
    Maybe physics.open.ac.uk/~dbroadhu/cert/semgpch.gp is of interest.
    $endgroup$
    – gammatester
    Dec 8 '18 at 22:34










  • $begingroup$
    It's unclear how one could be certain that a large number was a semiprime (as opposed to having three or more prime factors) without knowing the two prime factors which multiply to it.
    $endgroup$
    – Keith Backman
    Dec 9 '18 at 2:33










  • $begingroup$
    @KeithBackman Surprisingly, this seems to be possible. I heard from a construction of a number which could be proven to be semiprime without known factors (according to the claim, not even by the constructor himself). For huge number, this method is probably not feasible.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:11
















$begingroup$
I feel like a list of "possible semiprimes" would likely be at least somewhat coincident with a list of possible primes, given that a large semiprime accordingly has large prime factors (so finding said factors would be difficult, thus rendering the number a possible candidate for either). As for finding large semiprimes, I feel the easiest method would just be to multiply two large known primes together, but I imagine you want something more elegant.
$endgroup$
– Eevee Trainer
Dec 8 '18 at 22:27




$begingroup$
I feel like a list of "possible semiprimes" would likely be at least somewhat coincident with a list of possible primes, given that a large semiprime accordingly has large prime factors (so finding said factors would be difficult, thus rendering the number a possible candidate for either). As for finding large semiprimes, I feel the easiest method would just be to multiply two large known primes together, but I imagine you want something more elegant.
$endgroup$
– Eevee Trainer
Dec 8 '18 at 22:27












$begingroup$
Maybe physics.open.ac.uk/~dbroadhu/cert/semgpch.gp is of interest.
$endgroup$
– gammatester
Dec 8 '18 at 22:34




$begingroup$
Maybe physics.open.ac.uk/~dbroadhu/cert/semgpch.gp is of interest.
$endgroup$
– gammatester
Dec 8 '18 at 22:34












$begingroup$
It's unclear how one could be certain that a large number was a semiprime (as opposed to having three or more prime factors) without knowing the two prime factors which multiply to it.
$endgroup$
– Keith Backman
Dec 9 '18 at 2:33




$begingroup$
It's unclear how one could be certain that a large number was a semiprime (as opposed to having three or more prime factors) without knowing the two prime factors which multiply to it.
$endgroup$
– Keith Backman
Dec 9 '18 at 2:33












$begingroup$
@KeithBackman Surprisingly, this seems to be possible. I heard from a construction of a number which could be proven to be semiprime without known factors (according to the claim, not even by the constructor himself). For huge number, this method is probably not feasible.
$endgroup$
– Peter
Dec 9 '18 at 14:11




$begingroup$
@KeithBackman Surprisingly, this seems to be possible. I heard from a construction of a number which could be proven to be semiprime without known factors (according to the claim, not even by the constructor himself). For huge number, this method is probably not feasible.
$endgroup$
– Peter
Dec 9 '18 at 14:11










1 Answer
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$begingroup$

It doesn't exist. Any area of rectangle which sides are prime is a semiprime.






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    $begingroup$
    There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:13













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1 Answer
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1 Answer
1






active

oldest

votes









active

oldest

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active

oldest

votes









0












$begingroup$

It doesn't exist. Any area of rectangle which sides are prime is a semiprime.






share|cite|improve this answer









$endgroup$









  • 1




    $begingroup$
    There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:13


















0












$begingroup$

It doesn't exist. Any area of rectangle which sides are prime is a semiprime.






share|cite|improve this answer









$endgroup$









  • 1




    $begingroup$
    There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:13
















0












0








0





$begingroup$

It doesn't exist. Any area of rectangle which sides are prime is a semiprime.






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$endgroup$



It doesn't exist. Any area of rectangle which sides are prime is a semiprime.







share|cite|improve this answer












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answered Dec 9 '18 at 2:24









usirousiro

32539




32539








  • 1




    $begingroup$
    There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:13
















  • 1




    $begingroup$
    There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
    $endgroup$
    – Peter
    Dec 9 '18 at 14:13










1




1




$begingroup$
There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
$endgroup$
– Peter
Dec 9 '18 at 14:13






$begingroup$
There are also infinite many primes, but nevertheless it makes sense to speak of the largest known prime.
$endgroup$
– Peter
Dec 9 '18 at 14:13




















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