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 A375609 #7 Aug 21 2024 11:24:25
%S A375609 1,1,2,0,-24,-240,-1800,-10080,-20160,665280,15120000,219542400,
%T A375609 2335132800,11416204800,-272432160000,-11126129414400,
%U A375609 -252293974732800,-4099297608806400,-36217872365875200,593695670606438400,41572213064718336000,1335024565711828992000
%N A375609 Expansion of e.g.f. 1 / (exp(x^3) - x).
%F A375609 a(n) = n! * Sum_{k=0..floor(n/3)} (-n+3*k-1)^k/k!.
%o A375609 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(exp(x^3)-x)))
%o A375609 (PARI) a(n) = n!*sum(k=0, n\3, (-n+3*k-1)^k/k!);
%Y A375609 Cf. A089148, A375608.
%K A375609 sign
%O A375609 0,3
%A A375609 _Seiichi Manyama_, Aug 21 2024