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 A357028 #14 Sep 12 2022 03:20:32 %S A357028 1,0,2,6,82,820,13568,235368,5111748,123205248,3404436312, %T A357028 103998026880,3516027852456,129715202957184,5198615642907360, %U A357028 224652658604613120,10419411912935774736,516120552745366247424,27198524267826237745824 %N A357028 E.g.f. satisfies A(x) = (1 - x * A(x))^log(1 - x * A(x)). %F A357028 E.g.f. satisfies log(A(x)) = log(1 - x * A(x))^2. %F A357028 a(n) = Sum_{k=0..floor(n/2)} (2*k)! * (n+1)^(k-1) * |Stirling1(n,2*k)|/k!. %t A357028 m = 20; (* number of terms *) %t A357028 A[_] = 0; %t A357028 Do[A[x_] = (1 - x*A[x])^Log[1 - x*A[x]] + O[x]^m // Normal, {m}]; %t A357028 CoefficientList[A[x], x]*Range[0, m - 1]! (* _Jean-François Alcover_, Sep 12 2022 *) %o A357028 (PARI) a(n) = sum(k=0, n\2, (2*k)!*(n+1)^(k-1)*abs(stirling(n, 2*k, 1))/k!); %Y A357028 Cf. A001761, A357029. %Y A357028 Cf. A357036. %K A357028 nonn %O A357028 0,3 %A A357028 _Seiichi Manyama_, Sep 09 2022