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 A370511 #17 Feb 20 2024 13:47:10
%S A370511 1,1,2,6,25,124,738,5137,40926,367236,3664321,40241168,482282700,
%T A370511 6263450401,87618831730,1313438757210,21003941166601,356910563528412,
%U A370511 6422026243338846,121980432505328545,2438957859604373534,51206341993873093608,1126314833020691642497
%N A370511 Expansion of Sum_{k>=0} k! * ( x/(1-x^3) )^k.
%F A370511 a(n) = Sum_{k=0..floor(n/3)} (n-3*k)! * binomial(n-2*k-1,k).
%o A370511 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, k!*(x/(1-x^3))^k))
%o A370511 (PARI) a(n) = sum(k=0, n\3, (n-3*k)!*binomial(n-2*k-1, k));
%Y A370511 Cf. A001339, A276080.
%Y A370511 Cf. A358493.
%K A370511 nonn,easy
%O A370511 0,3
%A A370511 _Seiichi Manyama_, Feb 20 2024