A159592 G.f.: Sum_{n>=0} a(n)*x^n/2^(n(n-1)/2) = exp( Sum_{n>=1} A(x/2^n)^n*x^n/n ).

1, 1, 3, 17, 177, 3491, 133261, 9917307, 1443008813, 411772442315, 231163433300285, 255964900099068155, 560177408302962464013, 2427068640913282843197355, 20848444510025384551575108829

Offset

0,3

Links

Table of n, a(n) for n=0..14.

Example

G.f.: A(x) = 1 + x + 3*x^2/2 + 17*x^3/2^3 + 177*x^4/2^6 + 3491*x^5/2^10 +...
log(A(x)) = A(x/2)*x + A(x/4)^2*x^2/2 + A(x/8)^3*x^3/3 + A(x/16)^4*x^4/4 +...

Prog

(PARI) {a(n)=local(A=1+x); for(n=2, n, A=exp(sum(k=1, n, subst(A, x, x/2^k+x*O(x^n))^k*x^k/k))); 2^(n*(n-1)/2)*polcoeff(A, n)}

Crossrefs

Cf. A157675.

Sequence in context: A015083 A263460 A053934 * A126443 A054976 A304863

Adjacent sequences: A159589 A159590 A159591 * A159593 A159594 A159595

Keyword

nonn

Author

Paul D. Hanna, May 02 2009

Status

approved