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 A360774 #9 Feb 20 2023 07:50:49
%S A360774 1,1,5,31,284,3390,49878,871465,17620450,404554997,10394845097,
%T A360774 295485704544,9205957047661,311922101632409,11419004058232897,
%U A360774 449146827324857447,18889836751306735360,845892838094616177138,40182354573647684880446
%N A360774 Expansion of Sum_{k>=0} (x * (k + x))^k.
%F A360774 a(n) = Sum_{k=0..floor(n/2)} (n-k)^(n-2*k) * binomial(n-k,k).
%o A360774 (PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (x*(k+x))^k))
%o A360774 (PARI) a(n) = sum(k=0, n\2, (n-k)^(n-2*k)*binomial(n-k, k));
%Y A360774 Cf. A360775, A360776.
%Y A360774 Cf. A360611, A360618.
%K A360774 nonn
%O A360774 0,3
%A A360774 _Seiichi Manyama_, Feb 20 2023