A090696 - OEIS

%I #20 Sep 03 2019 03:29:12

%S 4,8,10,18,20,28,32,38,42,48,52,62,70,78,80,90,118,120,130,148,158,

%T 160,172,182,200,210,218,228,230,232,238,248,252,258,260,262,270,272,

%U 290,298,300,302,318,340,342,350,358,360,370,372,378,388,398,410,412,420

%N Numbers k such that k^2 - 11 is a prime.

%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 Daniel Starodubtsev, <a href="/A090696/b090696.txt">Table of n, a(n) for n = 1..5000</a>

%F a(n) = 2*A091271(n).

%t Select[Range[4,1200],PrimeQ[#^2-11]&] (* _Vladimir Joseph Stephan Orlovsky_, Feb 27 2011*)

%Y A091272 gives primes, A091273 gives prime index.

%K nonn

%O 1,1

%A _Giovanni Teofilatto_, Dec 20 2003

%E Extended by _Ray Chandler_, Dec 27 2003