OFFSET
0,2
FORMULA
G.f.: A(x) = [x^n] * Product_{k=0..n} 1/(1 - binomial(n,k)*x).
EXAMPLE
a(0) = 1 = [x^0] 1/(1-x);
a(1) = 2 = [x^1] 1/((1-x)(1-x));
a(2) = 11 = [x^2] 1/((1-x)(1-2x)(1-x));
a(3) = 184 = [x^3] 1/((1-x)(1-3x)(1-3x)(1-x));
a(4) = 10121 = [x^4] 1/((1-x)(1-4x)(1-6x)(1-4x)(1-x));
a(5) = 1911956 = [x^5] 1/((1-x)(1-5x)(1-10x)(1-10x)(1-5x)(1-x)); ...
MATHEMATICA
a[n_] := SeriesCoefficient[Product[1/(1 - Binomial[n, k]*x) , {k, 0, n}], {x, 0, n}];
Table[a[n], {n, 0, 14}] (* Jean-François Alcover, Jul 01 2017 *)
PROG
(PARI) {a(n)=polcoeff(1/prod(j=0, n, 1-binomial(n, j)*x +x*O(x^n)), n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 09 2006
STATUS
approved