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 A375715 #8 Aug 25 2024 09:58:26
%S A375715 1,0,0,3,6,10,285,1911,8848,147456,1818225,15966775,244374636,
%T A375715 4105980528,55574016589,938220142965,18765940185840,342231152117536,
%U A375715 6765035069902833,154060159512672315,3469311695227952260,80672955862303202160,2068943441492081794101
%N A375715 Expansion of e.g.f. 1 / sqrt(1 - x^2 * (exp(x) - 1)).
%F A375715 a(n) = n! * Sum_{k=0..floor(n/3)} A001147(k) * Stirling2(n-2*k,k)/(2^k*(n-2*k)!).
%o A375715 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/sqrt(1-x^2*(exp(x)-1))))
%o A375715 (PARI) a001147(n) = prod(k=0, n-1, 2*k+1);
%o A375715 a(n) = n!*sum(k=0, n\3, a001147(k)*stirling(n-2*k, k, 2)/(2^k*(n-2*k)!));
%Y A375715 Cf. A001147, A358013, A375698.
%K A375715 nonn
%O A375715 0,4
%A A375715 _Seiichi Manyama_, Aug 25 2024