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 A347985 #36 Sep 24 2021 16:35:14
%S A347985 1,-3,131,-8955,893249,-117408375,19180128407,-3747886705563,
%T A347985 852713408774513,-221431482383149467,64629367172619230475,
%U A347985 -20945446993569455512155,7463226827397324296491489,-2899926767958744905966692575
%N A347985 a(n) = [x^n] (2*n)! * Sum_{k=0..2*n} binomial(x-2*n,k).
%H A347985 Seiichi Manyama, <a href="/A347985/b347985.txt">Table of n, a(n) for n = 0..283</a>
%F A347985 a(n) = A054649(2*n,n).
%o A347985 (PARI) a(n) = (2*n)!*polcoef(sum(k=n, 2*n, binomial(x-2*n, k)), n);
%Y A347985 Cf. A054649.
%K A347985 sign
%O A347985 0,2
%A A347985 _Seiichi Manyama_, Sep 24 2021