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 A239795 #8 May 24 2024 15:16:17
%S A239795 1,3,5,21,45,11,91,45,17,1995,3465,115,2925,189,145,341,1309,1,9139,
%T A239795 65,2255,148995,108675,1645,270725,21879,583,4389,4959,59,1548729,
%U A239795 27027,60775,130985,15525,1065,66047553,2567565,39,2133,56457,1411,8161615,2639
%N A239795 a(n) = A239793(n)/2^(3*n).
%C A239795 See A239792 for references.
%F A239795 Let b(n) = -Sum_{2<=k<=n} (C(n-1, k-1)*Bernoulli(k)*b(n-k)/k)/2
%F A239795 for n>0 and otherwise 1. Then a(n) = denominator(b(2*n))/2^(3*n).
%p A239795 b := proc(n) option remember; if n < 1 then 1 else
%p A239795 -add(binomial(n-1, k-1)*bernoulli(k)*b(n-k)/k, k= 2..n)/2 fi end:
%p A239795 A239795 := n -> denom(b(2*n))/2^(3*n):
%p A239795 seq(A239795(n), n=0..43);
%Y A239795 Cf. A220412, A239792.
%K A239795 nonn
%O A239795 0,2
%A A239795 _Peter Luschny_, Mar 26 2014