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 A377860 #9 Nov 10 2024 05:02:11
%S A377860 1,1,5,44,577,10104,222133,5886880,182775969,6509571200,261665344261,
%T A377860 11720054882304,578878362625825,31259890045425664,1832295378792935925,
%U A377860 115862322601669627904,7861907382202262095297,569837358810005613281280,43939338917141224534941829
%N A377860 Expansion of e.g.f. (1/x) * Series_Reversion( x * (1 - x)^2 * exp(x) ).
%H A377860 <a href="/index/Res#revert">Index entries for reversions of series</a>
%F A377860 E.g.f. A(x) satisfies A(x) = exp(-x * A(x))/(1 - x*A(x))^2.
%F A377860 a(n) = n! * Sum_{k=0..n} (-1)^k * (n+1)^(k-1) * binomial(3*n-k+1,n-k)/k!.
%o A377860 (PARI) a(n) = n!*sum(k=0, n, (-1)^k*(n+1)^(k-1)*binomial(3*n-k+1, n-k)/k!);
%Y A377860 Cf. A377859, A377861.
%Y A377860 Cf. A377832.
%K A377860 nonn
%O A377860 0,3
%A A377860 _Seiichi Manyama_, Nov 09 2024