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 A277296 #9 Oct 11 2016 18:42:30
%S A277296 0,5,76,698,5088,32461,189940,1046190,5511440,28061890,139089880,
%T A277296 674600980,3213923072,15084364221,69904629316,320443984742,
%U A277296 1455102018480,6553035703798,29296998868904,130133568013164,574698326054848,2524813186117010,11040163152179976,48069234287414668,208481908639356448,900995206054983396,3881108155492099760
%N A277296 Column 2 of triangle A277295; a(n) = A277295(n+2,2).
%C A277296 G.f. G(x,y) of triangle A277295 satisfies:
%C A277296 (1) G(x,y) = x + G( y*G(x,y) + (1-y)*x, y)^2.
%C A277296 (2) G( x - y*G(x,y)^2, y) = x + (1-y)*G(x,y)^2.
%o A277296 (PARI) {A277295(n,k) = my(A=x); for(i=1, n, A = x + subst(A^2, x, y*A + (1-y)*x +x*O(x^n)) ); polcoeff(polcoeff(A,n,x),k,y)}
%o A277296 for(n=1,30,print1(A277295(n+2,2),", "))
%Y A277296 Cf. A277295, A277297, A277298, A277299.
%K A277296 nonn
%O A277296 1,2
%A A277296 _Paul D. Hanna_, Oct 11 2016