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 A353288 #11 Apr 10 2022 02:21:11
%S A353288 1,0,1,1,2,7,30,139,723,4487,33551,289854,2774999,29016343,333139222,
%T A353288 4232908176,59442337179,912948755487,15154215501815,269933506466203,
%U A353288 5150440487875190,105326085645729766,2307425141636199329,53998118146846356916,1343998910355295080556
%N A353288 a(n) = Sum_{k=0..floor(n/2)} k^(n-2*k) * Stirling2(n-k,k).
%F A353288 G.f.: Sum_{k>=0} x^(2*k)/Product_{j=1..k} (1 - k * j * x).
%o A353288 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, x^(2*k)/prod(j=1, k, 1-k*j*x)))
%o A353288 (PARI) a(n) = sum(k=0, n\2, k^(n-2*k)*stirling(n-k, k, 2));
%Y A353288 Cf. A119429, A171367, A353262.
%Y A353288 Cf. A104872, A353287.
%K A353288 nonn
%O A353288 0,5
%A A353288 _Seiichi Manyama_, Apr 09 2022