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 A349087 #9 Apr 05 2022 17:08:43
%S A349087 1,1,2,6,23,115,690,4830,38641,347769,3477690,38254590,459055079,
%T A349087 5967716027,83548024378,1253220365670,20051525850721,340875939462257,
%U A349087 6135766910320626,116579571296091894,2331591425921837879,48963419944358595459,1077195238775889100098
%N A349087 a(n) = n! * Sum_{k=0..floor(n/4)} (-1)^k / (4*k)!.
%F A349087 E.g.f.: cos(x/sqrt(2)) * cosh(x/sqrt(2)) / (1 - x).
%F A349087 a(n) = round(c * n!), where c = 0.9583581... = A346440.
%t A349087 Table[n! Sum[(-1)^k/(4 k)!, {k, 0, Floor[n/4]}], {n, 0, 22}]
%t A349087 nmax = 22; CoefficientList[Series[Cos[x/Sqrt[2]] Cosh[x/Sqrt[2]]/(1 - x), {x, 0, nmax}], x] Range[0, nmax]!
%Y A349087 Cf. A000166, A009102, A346440, A348597, A352660.
%K A349087 nonn
%O A349087 0,3
%A A349087 _Ilya Gutkovskiy_, Mar 25 2022