OFFSET
0,3
COMMENTS
In table A122888, row n lists the coefficients of x^k, k=1..2^n, in the n-th self-composition of (x + x^2) for n>=0.
LINKS
Paul D. Hanna, Table of n, a(n), n=0..100.
PROG
(PARI) {a(n)=local(F=x+x^2, G, RS); RS=0; for(k=0, n, G=x+x*O(x^n); for(i=1, n-k, G=subst(F, x, G)); RS+=polcoeff(G, k, x)); RS} \\ Paul D. Hanna, Nov 28 2009
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 18 2006
STATUS
approved