Prime Nos

This is a discussion on Prime Nos within the A Brief History of Cprogramming.com forums, part of the Community Boards category; Searched google but was not sucessfull in finding the info... How many 256 bit (around 64 digit long) prime numbers ...

  1. #1
    Its not rocket science vasanth's Avatar
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    Prime Nos

    Searched google but was not sucessfull in finding the info...

    How many 256 bit (around 64 digit long) prime numbers are there and any site which lists them all....


    thanx in advance

  2. #2
    and the hat of int overfl Salem's Avatar
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    http://mathworld.wolfram.com/PrimeNumberTheorem.html
    Up to a number n, there are approximately n/log(n) primes

    So just do the calc for 2^256 and 2^257 and you have an approximate answer

    I think you'll find that the number of primes is pretty large - so large that a list of them would be infeasable at best

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    C++ Developer XSquared's Avatar
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    There are about 6.4747x10^74 primes between 2^256 and 2^257. Good luck getting a list.
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    Here's a do it yourself kit (some assembly required)
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    Toaster Zach L.'s Avatar
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    Primes? You want primes? Here ya go:
    (k+2){1 – [wz+h+j–q]2 – [(gk+2g+k+1)(h+j)+h–z]2 – [2n+p+q+z–e]2 – [16(k+1)3(k+2)(n+1)2+1–f2]2 – [e3(e+2)(a+1)2+1–o2]2 – [(a2–1)y2+1–x2]2 – [16r2y4(a2–1)+1–u2]2 – [((a+u2(u2–a))2 –1)(n+4dy)2 + 1 – (x+cu)2]2 – [n+l+v–y]2 – [(a2–1)l2+1–m2]2 – [ai+k+1–l–i]2 – [p+l(a–n–1)+b(2an+2a–n2–2n–2)–m]2 – [q+y(a–p–1)+s(2ap+2a–p2–2p–2)–x]2 – [z+pl(a–p)+t(2ap–p2–1)–pm]2}
    Just grab the positive values of it with (a, b, ..., z) included in Z\(Z-).
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  6. #6
    Its not rocket science vasanth's Avatar
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    hmmm i dint expect so many to be there since I though longer the number of digits lesser the prime numbers... looks like 64 wasnt long enough.. thanx anyway

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