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.
%I A066436 #48 Sep 08 2022 08:45:04
%S A066436 7,17,31,71,97,127,199,241,337,449,577,647,881,967,1151,1249,1567,
%T A066436 2311,2591,2887,3041,3361,3527,3697,4049,4231,4801,4999,5407,6271,
%U A066436 6961,7687,7937,8191,9521,10657,11551,12799,13121,14449,15137,16561
%N A066436 Primes of the form 2*n^2 - 1.
%C A066436 It is conjectured that this sequence is infinite.
%C A066436 Also primes p such that 8p + 8 is a square. - _Cino Hilliard_, Dec 18 2003
%C A066436 Also primes p such that 2p+2 is square; also primes p such that (p+1)/2 is square. - _Ray Chandler_, Sep 15 2005
%C A066436 Arithmetic numbers which are squares, A003601(p)=A000290(k), p prime, k integer. sigma_1(p)/sigma_0(p)=k^2; p prime, k integer. - _Ctibor O. Zizka_, Jul 14 2008
%D A066436 D. Shanks, Solved and Unsolved Problems in Number Theory, 2nd. ed., Chelsea, 1978, p. 31.
%H A066436 Harry J. Smith, <a href="/A066436/b066436.txt">Table of n, a(n) for n = 1..1000</a>
%H A066436 Project Euler, <a href="https://projecteuler.net/problem=216">Problem 216: Investigating the primality of numbers of the form 2n^2-1</a>.
%t A066436 Select[2*Range[200]^2-1,PrimeQ] (* _Harvey P. Dale_, Aug 29 2016 *)
%o A066436 (Magma) [ p: n in [1..100] | IsPrime(p) where p is 2*n^2-1 ]; // _Klaus Brockhaus_, Dec 29 2008
%o A066436 (PARI) { n=0; for (m=1, 10^9, p=2*m^2 - 1; if (isprime(p), write("b066436.txt", n++, " ", p); if (n==1000, return)) ) } \\ _Harry J. Smith_, Feb 14 2010
%Y A066436 See A066049 for the values of n, see A091176 for prime index.
%Y A066436 Cf. A090697, A110558, A003601, A000290.
%K A066436 nonn
%O A066436 1,1
%A A066436 _N. J. A. Sloane_, Jan 09 2002