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 A328183 #5 Oct 06 2019 10:05:14
%S A328183 1,4,48,832,19200,553984,19181568,774848512,35771842560,1857882947584,
%T A328183 107214340620288,6805814291464192,471298297319915520,
%U A328183 35356865248765149184,2856513752723261227008,247264693517100223823872,22830563015939200206766080,2239752722978295095737974784
%N A328183 Expansion of e.g.f. 1 / (2 - exp(4*x)).
%F A328183 a(0) = 1; a(n) = Sum_{k=1..n} 4^k * binomial(n,k) * a(n-k).
%F A328183 a(n) = Sum_{k>=0} (4*k)^n / 2^(k + 1).
%F A328183 a(n) = 4^n * A000670(n).
%p A328183 a:= proc(n) option remember; `if`(n=0, 1, add(
%p A328183 a(n-j)*binomial(n, j)*4^j, j=1..n))
%p A328183 end:
%p A328183 seq(a(n), n=0..20); # _Alois P. Heinz_, Oct 06 2019
%t A328183 nmax = 17; CoefficientList[Series[1/(2 - Exp[4 x]), {x, 0, nmax}], x] Range[0, nmax]!
%t A328183 a[0] = 1; a[n_] := a[n] = Sum[4^k Binomial[n, k] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 17}]
%t A328183 Table[2^(2 n - 1) HurwitzLerchPhi[1/2, -n, 0], {n, 0, 17}]
%Y A328183 Cf. A000670, A216794, A328182.
%K A328183 nonn
%O A328183 0,2
%A A328183 _Ilya Gutkovskiy_, Oct 06 2019