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 A357903 #9 Oct 19 2022 13:40:31
%S A357903 1,0,0,1,1,1,2,4,8,17,38,89,219,567,1543,4400,13094,40507,129874,
%T A357903 430731,1476030,5222544,19066758,71764369,278166767,1108986222,
%U A357903 4541765652,19085377108,82211094414,362717859475,1638071537802,7567876937002,35748311794246,172558399424154
%N A357903 a(n) = Sum_{k=0..floor(n/3)} Stirling2(n - 2*k,k).
%F A357903 G.f.: Sum_{k>=0} x^(3*k)/Product_{j=1..k} (1 - j * x).
%o A357903 (PARI) a(n) = sum(k=0, n\3, stirling(n-2*k, k, 2));
%o A357903 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, x^(3*k)/prod(j=1, k, 1-j*x)))
%Y A357903 Cf. A000110, A171367, A357904.
%K A357903 nonn
%O A357903 0,7
%A A357903 _Seiichi Manyama_, Oct 19 2022