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 A356970 #10 Sep 12 2022 03:05:37
%S A356970 1,0,0,6,12,40,1980,16128,136080,4224960,70943040,1087178400,
%T A356970 31274100000,784834652160,18115033128192,565994928945600,
%U A356970 18161466717139200,560655551681971200,20108422243585658880,769928646324249699840,29464638272901949824000
%N A356970 E.g.f. satisfies A(x) = 1/(1 - x * A(x))^(x^2 * A(x)).
%F A356970 a(n) = n! * Sum_{k=0..floor(n/3)} (n-k+1)^(k-1) * |Stirling1(n-2*k,k)|/(n-2*k)!.
%t A356970 m = 21; (* number of terms *)
%t A356970 A[_] = 0;
%t A356970 Do[A[x_] = 1/(1 - x*A[x])^(x^2*A[x]) + O[x]^m // Normal, {m}];
%t A356970 CoefficientList[A[x], x]*Range[0, m - 1]! (* _Jean-François Alcover_, Sep 12 2022 *)
%o A356970 (PARI) a(n) = n!*sum(k=0, n\3, (n-k+1)^(k-1)*abs(stirling(n-2*k, k, 1))/(n-2*k)!);
%Y A356970 Cf. A184949, A349556, A356971.
%Y A356970 Cf. A356967.
%K A356970 nonn
%O A356970 0,4
%A A356970 _Seiichi Manyama_, Sep 07 2022