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 A349858 #18 Dec 11 2021 04:29:33
%S A349858 1,1,0,-14,175,2211,-400994,25610260,582496701,-666933657755,
%T A349858 166042332973276,-14222991979095594,-14297382182023795925,
%U A349858 12622343477815735821511,-5840589387156997753180230,-443718496524920696265166664,5189349322544398120691167482361
%N A349858 Expansion of Sum_{k>=0} x^k/(1 + k^4 * x).
%H A349858 Seiichi Manyama, <a href="/A349858/b349858.txt">Table of n, a(n) for n = 0..196</a>
%F A349858 a(n) = Sum_{k=0..n} (-k^4)^(n-k).
%t A349858 a[n_] := Sum[If[k == n - k == 0, 1, (-k^4)^(n-k)], {k, 0, n}]; Array[a, 17, 0] (* _Amiram Eldar_, Dec 03 2021 *)
%o A349858 (PARI) a(n, s=0, t=4) = sum(k=0, n, (-k^t)^(n-k)*k^s);
%o A349858 (PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, x^k/(1+k^4*x)))
%Y A349858 Cf. A349856, A349857.
%K A349858 sign
%O A349858 0,4
%A A349858 _Seiichi Manyama_, Dec 02 2021