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 A360810 #10 Feb 22 2023 10:20:11 %S A360810 1,1,1,2,5,11,29,81,229,696,2181,7045,23653,81433,288173,1046814, %T A360810 3887749,14768783,57275541,226462801,912443397,3741515804,15603500797, %U A360810 66134448329,284660214181,1243605590897,5511058189989,24760003963802,112726590916645 %N A360810 Expansion of Sum_{k>=0} ( x / (1 - k * x^2) )^k. %F A360810 a(n) = Sum_{k=0..floor(n/2)} (n-2*k)^k * binomial(n-k-1,k). %o A360810 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, (x/(1-k*x^2))^k)) %o A360810 (PARI) a(n) = sum(k=0, n\2, (n-2*k)^k*binomial(n-k-1, k)); %Y A360810 Cf. A324158, A360782. %K A360810 nonn %O A360810 0,4 %A A360810 _Seiichi Manyama_, Feb 21 2023