A143436 - OEIS

%I #2 Mar 30 2012 18:37:11

%S 1,1,4,26,216,2091,22532,263302,3282572,43184125,594892016,8533187394,

%T 126911650416,1950679300314,30905935176876,503694878376602,

%U 8429969774716104,144679270141457684,2543281262706638148

%N G.f. satisfies: A(x) = 1 + x*A(x*A(x))^4.

%F G.f. satisfies: x - G(x) = G(x)^2*A(x)^4 where G(x*A(x)) = x.

%e G.f.: A(x) = 1 + x + 4*x^2 + 26*x^3 + 216*x^4 + 2091*x^5 + 22532*x^6 +...

%e A(x*A(x)) = 1 + x + 5*x^2 + 38*x^3 + 356*x^4 + 3801*x^5 + 44508*x^6 +...

%e A(x*A(x))^4 = 1 + 4*x + 26*x^2 + 216*x^3 + 2091*x^4 + 22532*x^5 +...

%o (PARI) {a(n)=local(A=1+x+x*O(x^n));for(i=0,n,A=1+x*subst(A^4,x,x*A));polcoeff(A,n)}

%Y Cf. A143426, A143435, A143437.

%K nonn

%O 0,3

%A _Paul D. Hanna_, Aug 14 2008