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 A351745 #19 Apr 09 2022 13:23:42
%S A351745 1,1,1,2,4,7,7,-47,-549,-4284,-30756,-218315,-1571731,-11603343,
%T A351745 -88284675,-693810426,-5636074516,-47324368509,-410556832893,
%U A351745 -3677474325071,-33983530496537,-323712524813480,-3175734966375132,-32058728131612719,-332733970940411623,-3547642104951509087
%N A351745 Expansion of e.g.f. cos(x) * exp(exp(x) - 1).
%F A351745 a(n) = Sum_{k=0..floor(n/2)} (-1)^k * binomial(n,2*k) * Bell(n-2*k).
%t A351745 nmax = 25; CoefficientList[Series[Cos[x] Exp[Exp[x] - 1], {x, 0, nmax}], x] Range[0, nmax]!
%t A351745 Table[Sum[(-1)^k Binomial[n, 2 k] BellB[n - 2 k], {k, 0, Floor[n/2]}], {n, 0, 25}]
%o A351745 (PARI) my(x='x+O('x^30)); Vec(serlaplace(cos(x)*exp(exp(x) - 1))) \\ _Michel Marcus_, Apr 09 2022
%Y A351745 Cf. A000110, A009113, A224271, A352905.
%K A351745 sign
%O A351745 0,4
%A A351745 _Ilya Gutkovskiy_, Apr 07 2022