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 A302688 #6 Apr 12 2018 05:38:55
%S A302688 1,1,2,12,162,3888,144768,7693920,551981520,51355426992,6010929609408,
%T A302688 864202875949440,149698423474606080,30747550680449611200,
%U A302688 7388611598645058636000,2053517715502048081023360,653614372412684344833419520,236202930442590804658824312960
%N A302688 Expansion of 1 + x*(1 + 2*x*(1 + 3*x*(1 + 4*x*(1 + 5*x*(1 + ...)^5)^4)^3)^2).
%C A302688 (a(n) / n!^2)^(1/n) tends to 1.36594... - _Vaclav Kotesovec_, Apr 12 2018
%H A302688 Vaclav Kotesovec, <a href="/A302688/b302688.txt">Table of n, a(n) for n = 0..200</a>
%F A302688 G.f. A(x) = 1 + x + 2*x^2 + 12*x^3 + 162*x^4 + 3888*x^5 + 144768*x^6 + 7693920*x^7 + 551981520*x^8 + ...
%t A302688 nmax = 17; CoefficientList[Series[1 + x Fold[((#2 + 1) x #1 + 1)^#2 &, 0, Reverse[Range[nmax]]], {x, 0, nmax}], x]
%Y A302688 Cf. A095793, A128318, A128319, A138211, A138212.
%K A302688 nonn
%O A302688 0,3
%A A302688 _Ilya Gutkovskiy_, Apr 11 2018