A165940 G.f.: Sum_{n>=0} a(n)*x^n/2^(n^2+n) = exp( Sum_{n>=1} x^n/[n*2^(n^2)] ).

1, 2, 10, 152, 7684, 1352096, 852120928, 1960591940480, 16697154282192928, 531801639623740649984, 63854080509077223292639744, 29089348119991257994736112048128

Offset

0,2

Comments

Conjectured to consist entirely of integers.

Links

Table of n, a(n) for n=0..11.

Example

G.f.: 1 + 2*x/2^2 + 10*x^2/2^6 + 152*x^3/2^12 + 7684*x^4/2^20 +...
= exp( x/2 + x^2/(2*2^4) + x^3/(3*2^9) + x^4/(4*2^16) +... ).
Evaluated at x=1:
Sum_{n>=0} a(n)/2^(n^2+n) = 1.7021716250154556344906565654972646...

Prog

(PARI) {a(n)=2^(n^2+n)*polcoeff(exp(sum(m=1, n+1, 2^(-m^2)*x^m/m)+x*O(x^n)), n)}

Crossrefs

Cf. A155200.

Sequence in context: A086619 A294373 A194026 * A007080 A231517 A134088

Adjacent sequences: A165937 A165938 A165939 * A165941 A165942 A165943

Keyword

nonn

Author

Paul D. Hanna, Oct 01 2009

Status

approved