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 A294119 #18 Apr 30 2022 21:24:46
%S A294119 1,4,20,112,688,4544,31936,236800,1841408,14943232,126063616,
%T A294119 1101983744,9954734080,92714156032,888502796288,8746003922944,
%U A294119 88294183469056,912920984944640,9655688415674368,104353064578711552,1151244577906098176,12953223477921316864
%N A294119 Expansion of e.g.f.: exp(2*((1+x)^2 - 1)).
%H A294119 Seiichi Manyama, <a href="/A294119/b294119.txt">Table of n, a(n) for n = 0..655</a>
%F A294119 E.g.f.: exp(2*((1+x)^2 - 1)).
%F A294119 a(n) ~ 2^(n - 1/2) * n^(n/2) * exp(-1 + 2*sqrt(n) - n/2). - _Vaclav Kotesovec_, Oct 23 2017
%F A294119 a(n) = 4*a(n-1)+4*(n-1)*a(n-2). - _Robert Israel_, Jun 16 2020
%p A294119 f:= rectoproc({a(n)=4*a(n-1)+4*(n-1)*a(n-2),a(0)=1,a(1)=4},a(n),remember):
%p A294119 map(f, [$0..30]); # _Robert Israel_, Jun 16 2020
%t A294119 nmax = 20; CoefficientList[Series[E^(2*((1+x)^2 - 1)), {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Oct 23 2017 *)
%o A294119 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(2*((1+x)^2-1))))
%Y A294119 Column k=2 of A294118.
%K A294119 nonn
%O A294119 0,2
%A A294119 _Seiichi Manyama_, Oct 23 2017