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A124835 Row sums of triangle A124834. 2
1, 2, 4, 9, 25, 91, 444, 2920, 25996, 314752, 5201874, 117719942, 3658433597, 156505343943, 9234365056453, 752841451059559, 84938741035295776, 13279814559055121447, 2880581923860441220144, 867855593621657824023139 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..19.

FORMULA

G.f.: A(x) = Sum_{k>=0} x^n * Product_{k=0..n} 1/(1 - binomial(n,k)*x).

EXAMPLE

A(x) = 1/(1-x) + x/((1-x)(1-x)) + x^2/((1-x)(1-2x)(1-x)) + x^3/((1-x)(1-3x)(1-3x)(1-x)) + x^4/((1-x)(1-4x)(1-6x)(1-4x)(1-x)) +...

PROG

(PARI) {a(n)=sum(k=0, n, polcoeff(1/prod(j=0, k, 1-binomial(k, j)*x +x*O(x^n)), n-k))}

CROSSREFS

Cf. A124834, A124836.

Sequence in context: A173496 A173311 A127055 * A125799 A220880 A307317

Adjacent sequences:  A124832 A124833 A124834 * A124836 A124837 A124838

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Nov 09 2006

STATUS

approved

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Last modified August 11 15:10 EDT 2022. Contains 356066 sequences. (Running on oeis4.)