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 A377685 #13 Nov 04 2024 09:09:01
%S A377685 1,0,4,6,136,900,16308,229320,4691104,99156960,2481162480,67862678400,
%T A377685 2063842827264,68473763804160,2468786906210688,96048626176339200,
%U A377685 4010912604492410880,178968539487145282560,8496991445958129576960,427734144995749047152640
%N A377685 E.g.f. satisfies A(x) = (1 - x * log(1 - x*A(x)))^2.
%F A377685 E.g.f.: B(x)^2, where B(x) is the e.g.f. of A371227.
%F A377685 a(n) = 2 * n! * Sum_{k=0..floor(n/2)} (2*n-2*k+1)! * |Stirling1(n-k,k)|/( (n-k)! * (2*n-3*k+2)! ).
%o A377685 (PARI) a(n) = 2*n!*sum(k=0, n\2, (2*n-2*k+1)!*abs(stirling(n-k, k, 1))/((n-k)!*(2*n-3*k+2)!));
%Y A377685 Cf. A371117, A377686.
%Y A377685 Cf. A371227, A377390.
%K A377685 nonn
%O A377685 0,3
%A A377685 _Seiichi Manyama_, Nov 04 2024