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 A293721 #12 Oct 16 2017 12:39:08
%S A293721 1,1,9,79,457,5901,66841,720259,11155089,158315257,2361665161,
%T A293721 42133751991,720156599449,13181971424389,265545621153177,
%U A293721 5280775950377131,111888028465044001,2508562975185903729,56507353426001537929,1342159313030965211167
%N A293721 E.g.f.: exp(x + 4*x^2 + 9*x^3).
%H A293721 Seiichi Manyama, <a href="/A293721/b293721.txt">Table of n, a(n) for n = 0..497</a>
%F A293721 a(n) ~ 3^(n - 1/2) * n^(2*n/3) * exp(-392/6561 - 2*n/3 + 49*n^(1/3)/243 + 4*n^(2/3)/9). - _Vaclav Kotesovec_, Oct 15 2017
%t A293721 CoefficientList[Series[E^(x + 4*x^2 + 9*x^3), {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Oct 15 2017 *)
%o A293721 (PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(x+4*x^2+9*x^3)))
%Y A293721 Column k=3 of A293724.
%K A293721 nonn
%O A293721 0,3
%A A293721 _Seiichi Manyama_, Oct 15 2017