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 A245051 #6 Jul 10 2014 19:16:01
%S A245051 1,2,31,691,18054,515892,15615159,492007235,15968172965,530169356965,
%T A245051 17922457144129,614796956579459,21346411113410148,748762981653051898,
%U A245051 26493592534823331169,944491728494004127029,33892155096781949014406,1223212951343094980654244
%N A245051 Number of hybrid 8-ary trees with n internal nodes.
%H A245051 Alois P. Heinz, <a href="/A245051/b245051.txt">Table of n, a(n) for n = 0..300</a>
%H A245051 SeoungJi Hong and SeungKyung Park, <a href="http://dx.doi.org/10.4134/BKMS.2014.51.1.229">Hybrid d-ary trees and their generalization</a>, Bull. Korean Math. Soc. 51 (2014), No. 1, pp. 229-235
%F A245051 a(n) = 1/(7*n+1) * Sum_{i=0..n} C(7*n+i,i)*C(7*n+i+1,n-i).
%F A245051 a(n) = [x^n] ((1+x)/(1-x-x^2))^(7*n+1) / (7*n+1).
%F A245051 G.f. satisfies: A(x) = (1+x*A(x)^7) * (1+x*A(x)^8).
%p A245051 a:= n-> add(binomial(7*n+i, i)*binomial(7*n+i+1, n-i), i=0..n)/(7*n+1):
%p A245051 seq(a(n), n=0..20);
%Y A245051 Column k=8 of A245049.
%K A245051 nonn
%O A245051 0,2
%A A245051 _Alois P. Heinz_, Jul 10 2014