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 A255521 #11 Apr 14 2019 07:51:12
%S A255521 0,1,9,117,1866,32553,603414,11654634,232034283,4728048201,
%T A255521 98125181461,2066983603704,44079196497075,949772378078829,
%U A255521 20645820782745363,452215682045713701,9970925646977589555,221133330528834114000,4929622717525248345174,110400838255998014848137
%N A255521 Number of rooted identity trees with n nodes and 9-colored non-root nodes.
%H A255521 Alois P. Heinz, <a href="/A255521/b255521.txt">Table of n, a(n) for n = 0..700</a>
%F A255521 a(n) ~ c * d^n / n^(3/2), where d = 24.2805556948066926165789325334976292249076194687965619357813839307368..., c = 0.04399000859622510673129847184312171422452194... . - _Vaclav Kotesovec_, Feb 24 2015
%F A255521 From _Ilya Gutkovskiy_, Apr 14 2019: (Start)
%F A255521 G.f. A(x) satisfies: A(x) = x*exp(9*Sum_{k>=1} (-1)^(k+1)*A(x^k)/k).
%F A255521 G.f.: A(x) = Sum_{n>=1} a(n)*x^n = x * Product_{n>=1} (1 + x^n)^(9*a(n)). (End)
%p A255521 with(numtheory):
%p A255521 a:= proc(n) option remember; `if`(n<2, n, -add(a(n-j)*add(
%p A255521 9*a(d)*d*(-1)^(j/d), d=divisors(j)), j=1..n-1)/(n-1))
%p A255521 end:
%p A255521 seq(a(n), n=0..30);
%Y A255521 Column k=9 of A255517.
%K A255521 nonn
%O A255521 0,3
%A A255521 _Alois P. Heinz_, Feb 24 2015