cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A092057 Primes of the form 2*p^2 - 1, where p is prime.

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%I A092057 #14 Jun 26 2017 13:18:10
%S A092057 7,17,97,241,337,577,3361,3697,6961,10657,23761,25537,32257,37537,
%T A092057 49297,64081,65521,77617,79201,89041,126001,138337,153457,171697,
%U A092057 193441,249217,269377,287281,334561,351121,374977,474337,633937,652081,665857
%N A092057 Primes of the form 2*p^2 - 1, where p is prime.
%H A092057 T. D. Noe, <a href="/A092057/b092057.txt">Table of n, a(n) for n = 1..1000</a>
%t A092057 lst={};Do[p=Prime[n];If[PrimeQ[r=2*p^2-1],AppendTo[lst,r]],{n,6!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Jun 20 2009 *)
%t A092057 Select[2#^2-1&/@Prime[Range[200]],PrimeQ] (* _Harvey P. Dale_, Jun 26 2017 *)
%o A092057 (PARI) for (i=1,300,if(isprime(2*prime(i)^2-1),print1(2*prime(i)^2-1,",")))
%Y A092057 Cf. A092058.
%Y A092057 Cf. A106483 (primes p such that 2p^2 - 1 is also prime).
%K A092057 easy,nonn
%O A092057 1,1
%A A092057 Mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Feb 19 2004