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 A337027 #4 Aug 11 2020 19:48:24
%S A337027 1,3,24,293,4784,97687,2393472,68405073,2233928448,82063263371,
%T A337027 3349249267712,150353137462717,7362889615257600,390601858379350815,
%U A337027 22315011551291080704,1365896953310909493929,89179296762081886011392,6186383336743041502051219
%N A337027 a(n) = (1/2) * Sum_{k>=0} (2*k + n)^n / 2^k.
%F A337027 a(n) = n! * [x^n] exp(n*x) / (2 - exp(2*x)).
%F A337027 a(n) = Sum_{k=0..n} binomial(n,k) * n^k * A216794(n-k).
%t A337027 Table[2^(n - 1) HurwitzLerchPhi[1/2, -n, n/2], {n, 0, 17}]
%t A337027 Table[n! SeriesCoefficient[Exp[n x]/(2 - Exp[2 x]), {x, 0, n}], {n, 0, 17}]
%Y A337027 Cf. A080253, A162314, A216794, A292916.
%K A337027 nonn
%O A337027 0,2
%A A337027 _Ilya Gutkovskiy_, Aug 11 2020