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 A348587 #9 Oct 28 2021 02:07:51
%S A348587 1,1,0,-2,2,26,-30,-622,982,25846,-50910,-1639142,3874862,147434366,
%T A348587 -406614390,-17851478062,56266545142,2799621404086,-9927225631470,
%U A348587 -552054087163382,2175042302117822,133686372253841006,-579383205000618150,-39002628245713951102
%N A348587 Expansion of e.g.f. exp(x) / (2 - cos(x)).
%F A348587 a(n) = Sum_{k=0..floor(n/2)} (-1)^k * binomial(n,2*k) * A094088(k).
%t A348587 nmax = 23; CoefficientList[Series[Exp[x]/(2 - Cos[x]), {x, 0, nmax}], x] Range[0, nmax]!
%o A348587 (PARI) my(x='x+O('x^40)); Vec(serlaplace(exp(x)/(2-cos(x)))) \\ _Michel Marcus_, Oct 24 2021
%Y A348587 Cf. A003701, A094088, A327034, A348580.
%K A348587 sign
%O A348587 0,4
%A A348587 _Ilya Gutkovskiy_, Oct 24 2021