A156908 G.f.: A(x) = 1 + x*exp( Sum_{k>=1} [A(3^k*x) - 1]^k/k ).

1, 1, 3, 72, 10899, 13775400, 185126087574, 25804839804745266, 34576186149297464460939, 431016348991655088520874274528, 49345807665910247245278532420622266770

Offset

0,3

Comments

Conjectured to consist entirely of integers.

Links

Table of n, a(n) for n=0..10.

Example

G.f.: A(x) = 1 + x + 3*x^2 + 72*x^3 + 10899*x^4 + 13775400*x^5 +...
...
A(x) = 1 + x*exp( [A(3x)-1] + [A(9x)-1]^2/2 + [A(27x)-1]^3/3 +... ).

Prog

(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=1, n, A=1+x*exp(sum(k=1, n, (subst(A, x, 3^k*x+x*O(x^n))-1)^k/k))); polcoeff(A, n)}

Crossrefs

Cf. A156907.

Sequence in context: A332747 A202948 A213986 * A182517 A135866 A307925

Adjacent sequences: A156905 A156906 A156907 * A156909 A156910 A156911

Keyword

nonn

Author

Paul D. Hanna, Mar 04 2009

Status

approved