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 A292951 #21 Jul 10 2022 08:08:46
%S A292951 1,0,0,-6,-12,-20,330,2478,11704,-15192,-751050,-7817150,-38408172,
%T A292951 151402524,5793891922,69046056870,393083614320,-2517944476592,
%U A292951 -98819987200146,-1384209703077750,-9376308260215220,67288368700200900,3186749671049174538
%N A292951 Expansion of e.g.f. exp(x^2 * (1 - exp(x))).
%H A292951 Seiichi Manyama, <a href="/A292951/b292951.txt">Table of n, a(n) for n = 0..200</a>
%F A292951 From _Seiichi Manyama_, Jul 09 2022: (Start)
%F A292951 a(n) = n! * Sum_{k=0..floor(n/3)} (-1)^k * Stirling2(n-2*k,k)/(n-2*k)!.
%F A292951 a(0) = 1; a(n) = -(n-1)! * Sum_{k=3..n} k/(k-2)! * a(n-k)/(n-k)!. (End)
%t A292951 With[{nn=30},CoefficientList[Series[Exp[x^2 (1-Exp[x])],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Jul 16 2021 *)
%o A292951 (PARI) x='x+O('x^66); Vec(serlaplace(exp(x^2*(1-exp(x)))))
%o A292951 (PARI) a(n) = n!*sum(k=0, n\3, (-1)^k*stirling(n-2*k, k, 2)/(n-2*k)!); \\ _Seiichi Manyama_, Jul 09 2022
%o A292951 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=-(i-1)!*sum(j=3, i, j/(j-2)!*v[i-j+1]/(i-j)!)); v; \\ _Seiichi Manyama_, Jul 09 2022
%Y A292951 Column k=2 of A292894.
%Y A292951 Cf. A240989.
%K A292951 sign
%O A292951 0,4
%A A292951 _Seiichi Manyama_, Sep 27 2017