cp's OEIS Frontend

A227377 Limit of rows, when read in reverse, of triangle A227372.

%I A227377 #5 Jul 10 2013 01:03:08
%S A227377 1,2,4,9,14,27,46,71,113,185,280,409,614,899,1325,1892,2639,3717,5216,
%T A227377 7221,9990,13600,18315,24705,33190,44338,58998,78151,102492,133963,
%U A227377 174840,227180,294463,380480,489606,628157,801699,1019864,1295760,1641900,2074523
%N A227377 Limit of rows, when read in reverse, of triangle A227372.
%C A227377 The g.f. of triangle A227372 satisfies: G(x,q) = 1 + x*G(q*x,q)*G(x,q)^2.
%C A227377 What is the generating function for this sequence?
%e A227377 G.f.: A(x) = 1 + x + 2*x^2 + 6*x^3 + 18*x^4 + 59*x^5 + 199*x^6 + 693*x^7 +...
%o A227377 (PARI) /* G.f. of A227372: G(x,q) = 1 + x*G(q*x,q)*G(x,q)^2: */
%o A227377 {A227372(n,k)=local(G=1);for(i=1,n,G=1+x*subst(G,x,q*x)*G^2 +x*O(x^n));polcoeff(polcoeff(G,n,x),k,q)}
%o A227377 {a(n)=A227372(n+1, n*(n-1)/2)}
%o A227377 for(n=0,40,print1(a(n),", "))
%Y A227377 Cf. A227372, A227373.
%K A227377 nonn
%O A227377 0,2
%A A227377 _Paul D. Hanna_, Jul 10 2013