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 A377340 #19 Oct 27 2024 01:39:39
%S A377340 1,3,9,54,531,6498,101925,1920222,42251391,1067567850,30411486441,
%T A377340 965077330374,33764590958571,1291198144146498,53587639922183757,
%U A377340 2398901329112787630,115225387686206361495,5911249981088653607898,322592377196349009882513
%N A377340 E.g.f. satisfies A(x) = ( 1 + (exp(x*A(x)) - 1)/A(x) )^3.
%F A377340 E.g.f.: B(x)^3, where B(x) is the e.g.f. of A377348.
%F A377340 a(n) = 3 * Sum_{k=0..floor((3*n+3)/4)} (3*n-3*k+2)!/(3*n-4*k+3)! * Stirling2(n,k).
%o A377340 (PARI) a(n) = 3*sum(k=0, (3*n+3)\4, (3*n-3*k+2)!/(3*n-4*k+3)!*stirling(n, k, 2));
%Y A377340 Cf. A377326, A377339.
%Y A377340 Cf. A377348.
%K A377340 nonn
%O A377340 0,2
%A A377340 _Seiichi Manyama_, Oct 26 2024