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 A119653 #4 Mar 31 2012 13:20:26
%S A119653 5,7,11,1,23,1,1,1,47,59,1,1,83,1,1,107,1,1,1,1,1,1,167,179,1,1,1,1,1,
%T A119653 227,1,263,1,1,1,1,1,1,1,347,359,1,383,1,1,1,1,1,1,1,467,479,1,503,1,
%U A119653 1,1,1,1,563,1,587,1,1,1,1,1,1,1,1,1,719,1,1,1,1,1,1,1,1,839,1,863,1,1
%N A119653 Denominator of BernoulliB[2p] divided by 6, where p=Prime[n].
%C A119653 a(n) is equal to 1 or a safe prime p: (p-1)/2 is also prime, A005385[n] = 5,7,11,23,47,59,83,107,167,179,227,263,347,359,383,467,479,503,563,587,719,839,863,887,983,1019... The indices of primes in a(n) are n=1,2,3,5,9,10,13,16,23,24..=A072192[n] Indices of Sophie Germain primes: p and 2p+1 are primes.
%F A119653 a(n) = Denominator[BernoulliB[2Prime[n]]]/6.
%t A119653 Table[Denominator[BernoulliB[2Prime[n]]]/6,{n,1,100}]
%Y A119653 Cf. A002445, A005385, A072192, A005384, A079148.
%K A119653 nonn
%O A119653 1,1
%A A119653 _Alexander Adamchuk_, Jul 28 2006