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 A331660 #6 Jan 24 2020 20:57:15
%S A331660 1,1,5,32,280,3280,49480,927560,21037640,566134160,17803754560,
%T A331660 646052181520,26757321804880,1252934215973600,65791336312915520,
%U A331660 3846554938702140320,248841434876849499040,17713758333248102781760,1380631354206969100115200
%N A331660 E.g.f. A(x) satisfies: d/dx A(x) = 1 + (1/(1 - x)) * A(x/(1 - x)).
%F A331660 a(1) = 1; a(n+1) = Sum_{k=0..n-1} binomial(n,k)^2 * k! * a(n-k).
%t A331660 terms = 20; A[_] = 0; Do[A[x_] = Normal[Integrate[1 + 1/(1 - x) A[x/(1 - x) + O[x]^(terms + 1)], x] + O[x]^(terms + 1)], terms]; CoefficientList[A[x], x] Range[0, terms]! // Rest
%t A331660 a[1] = 1; a[n_] := a[n] = Sum[Binomial[n - 1, k]^2 k! a[n - k - 1], {k, 0, n - 2}]; Table[a[n], {n, 1, 20}]
%Y A331660 Cf. A001063, A110083, A132228, A331661.
%K A331660 nonn
%O A331660 1,3
%A A331660 _Ilya Gutkovskiy_, Jan 23 2020