login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

G.f. A(x) satisfies A(A(A(..(A(x))..))) = B(x) (6th self-COMPOSE of A) such that the coefficients of B(x) consist only of numbers {1,2,3,..,6}, with B(0) = 0.
3

%I #6 Mar 13 2015 00:07:10

%S 1,1,-4,28,-236,2159,-20309,189387,-1696165,14092143,-103605487,

%T 621674576,-2503235595,1311059747,58857366823,-625935119621,

%U 20416246154579,-595556154741631,9331660766550500,-50486760747953952,-816026626910008666

%N G.f. A(x) satisfies A(A(A(..(A(x))..))) = B(x) (6th self-COMPOSE of A) such that the coefficients of B(x) consist only of numbers {1,2,3,..,6}, with B(0) = 0.

%e A(x) = x + x^2 - 4*x^3 + 28*x^4 - 236*x^5 + 2159*x^6 +...

%e where A(A(A(A(A(A(x)))))) =

%e x + 6*x^2 + 6*x^3 + 3*x^4 + 4*x^5 + 4*x^6 + 6*x^7 + 2*x^8 +...

%e is the g.f. of A112112.

%o (PARI) {a(n,m=6)=local(F=x+x^2+x*O(x^n),G);if(n<1,0, for(k=3,n, G=F+x*O(x^k);for(i=1,m-1,G=subst(F,x,G)); F=F-((polcoeff(G,k)-1)\m)*x^k); return(polcoeff(F,n,x)))}

%Y Cf. A112112, A112104-A112111, A112114-A112127.

%K sign

%O 1,3

%A _Paul D. Hanna_, Aug 27 2005