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 A215691 #23 Feb 07 2021 07:04:20 %S A215691 1,1,4,18,124,950,8688,89600,1038392,13309272,186471480,2837173152, %T A215691 46466835072,815532508440,15246845864040,302533865599800, %U A215691 6344720827608384,140208886623418752,3254819745378435264,79172189409906466560,2013138139856523598080 %N A215691 n-th derivative of (x^x)^(x^(x^x)) at x=1. %C A215691 Also n-th derivative of (x^(x^(x^x)))^x = x^(x^(x^x)*x) at x=1. %H A215691 Alois P. Heinz, <a href="/A215691/b215691.txt">Table of n, a(n) for n = 0..400</a> %F A215691 E.g.f.: (x+1)^((x+1)^((x+1)^(x+1)+1)). %p A215691 a:= n-> n!*coeff(series(subs(x=x+1, (x^x)^(x^(x^x))), x, n+1), x, n): %p A215691 seq(a(n), n=0..30); %t A215691 m = 20; %t A215691 CoefficientList[(x+1)^((x+1)^((x+1)^(x+1)+1)) + O[x]^(m+1), x]*Range[0, m]! (* _Jean-François Alcover_, Feb 07 2021 *) %Y A215691 Column k=13 of A215703. %Y A215691 Cf. A005727, A179230, A179405, A215522, A215524, A215643. %K A215691 nonn %O A215691 0,3 %A A215691 _Alois P. Heinz_, Aug 20 2012