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