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 A277877 #18 Feb 28 2017 02:47:03
%S A277877 0,30,608,8740,109296,1269450,14096320,151927776,1603346160,
%T A277877 16659866938,171064877280
%N A277877 Number of A'Campo forests of degree n>1 and co-dimension 2.
%C A277877 We can prove this using generating functions.
%D A277877 P. Flajolet R. Sedgewick, Analytic Combinatorics, Cambridge University Press (2009)
%H A277877 N. Combe, V. Jugé, <a href="http://arxiv.org/abs/1702.07672">Counting bi-colored A'Campo forests</a>, arXiv:1702.07672 [math.AG], 2017.
%F A277877 a(n) is obtained by using the generating function N_{1} =1+yN_{2}^4 and (1-N_{2} +2yN_{2}^4 -yN_{2}^{5} +xyN_{2}^{6} +y^{2}N_{2}^{8})(1+yN_{2}^{4}-xyN_{2}^{5})+x^3y^{2}N_{2}^{9} =0, where N_{1}(x,y)=\sum_{n}N_{1}'(2,n)x^{2}y^{n} and N_{1}'(2,n) is the number of A'Campo forests with co-dimension 2; N_{2}(x,y)=\sum_{n}N_{2}'(2,n)x^{2}y^{n} where N_{2}'(2,n) is the number of partial configurations.
%e A277877 For n=3 we have a(3)=30 A'Campo forests of co-dimension 2.
%K A277877 nonn,more
%O A277877 1,2
%A A277877 _Noemie Combe_, Feb 27 2017