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 A090697 #15 Jul 23 2016 09:24:59 %S A090697 4,6,8,12,14,16,20,22,26,30,34,36,42,44,48,50,56,68,72,76,78,82,84,86, %T A090697 90,92,98,100,104,112,118,124,126,128,138,146,152,160,162,170,174,182, %U A090697 184,190,196,204,216,218,224,226,230,236,250,252,254,264,268,274,280 %N A090697 Numbers n such that n^2/2 - 1 is a prime. %C A090697 A066436 gives resulting primes p such that 2p+2 is square. - _Ray Chandler_, Dec 25 2003 %D A090697 M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988 %D A090697 Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997 %H A090697 Harvey P. Dale, <a href="/A090697/b090697.txt">Table of n, a(n) for n = 1..1000</a> %F A090697 a(n) = 2*A066049(n) = A110558(n)/2. - _Ray Chandler_, Dec 25 2003 %t A090697 Select[Range[2,300,2],PrimeQ[#^2/2-1]&] (* _Harvey P. Dale_, Apr 05 2014 *) %o A090697 (PARI) isok(n) = !(n % 2) && isprime(n^2/2 - 1); \\ _Michel Marcus_, Jul 23 2016 %Y A090697 Cf. A066049, A066436, A091176, A110558. %K A090697 easy,nonn %O A090697 1,1 %A A090697 _Giovanni Teofilatto_, Dec 20 2003 %E A090697 Corrected and extended by _Ray Chandler_, Dec 25 2003