Seriously disagreement
franktaw at netscape.net
franktaw at netscape.net
Wed Sep 3 00:31:28 CEST 2008
A closer look at this web page shows that this is counting the number
of
distinct prime divisors of numbers of the form 2x^2-1 for x <= 10^n,
not
the number of primes.
Note that there can be at most one prime divisor of 2x^2-1 that does
not divide 2y^2-1 for some y < x. Every prime divisor p except
possibly
one must be < 2x (in fact, p < sqrt(2) x), at which point p divides
2 |x-p|^2 - 1.
Franklin T. Adams-Watters
-----Original Message-----
From: Artur <grafix at csl.pl>
Dear Seqfans,
On www page
http://www.devalco.de/quadr_Sieb_2x%5E2-1.htm
we can read that number of primes of the form 2x^2-1 for x equal or
less
than 10^n is
8, 84, 815, 7922, 77250, 759077, 7492588, 74198995, 736401956,
7319543971, 72834161467
...
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