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 A360834 #13 Feb 23 2023 07:37:07
%S A360834 1,1,4,29,304,4100,67520,1314167,29520128,751658635,21393444864,
%T A360834 673046604600,23192501108736,868730852002205,35145114836811776,
%U A360834 1527192185786650417,70941146068492943360,3508043437942077557884,183989995827118805352448
%N A360834 Expansion of Sum_{k>=0} (k * x)^k / (1 - (k * x)^2)^(k+1).
%F A360834 a(n) = Sum_{k=0..floor(n/2)} (n-2*k)^n * binomial(n-k,k).
%o A360834 (PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (k*x)^k/(1-(k*x)^2)^(k+1)))
%o A360834 (PARI) a(n) = sum(k=0, n\2, (n-2*k)^n*binomial(n-k, k));
%Y A360834 Cf. A072034, A360835.
%Y A360834 Cf. A000045, A360782, A360787.
%K A360834 nonn
%O A360834 0,3
%A A360834 _Seiichi Manyama_, Feb 22 2023