A124382 O.g.f.: A(x) = Sum_{n>=0} x^n*Product_{k=0..n} (1 + k*(k+1)*(k+2)/6*x).

1, 1, 2, 6, 20, 90, 465, 2826, 20020, 158348, 1430189, 14217275, 157279196, 1903617880, 25151383277, 361228405394, 5594555181227, 93472423847492, 1671138501448565, 31988293954710201, 651665490924639449

Offset

0,3

Links

Table of n, a(n) for n=0..20.

Example

A(x) = 1 + x*(1+x) + x^2*(1+x)*(1+4x) + x^3*(1+x)*(1+4x)*(1+10x) +...

Prog

(PARI) a(n)=polcoeff(sum(k=0, n, x^k*prod(j=0, k, 1+j*(j+1)*(j+2)/3!*x+x*O(x^n))), n)

Crossrefs

Sequence in context: A241497 A003069 A079468 * A318813 A336544 A000666

Adjacent sequences: A124379 A124380 A124381 * A124383 A124384 A124385

Keyword

nonn

Author

Paul D. Hanna, Oct 28 2006

Status

approved