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Search: id:A107883
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A107883 Column 3 of triangle A107880. +0
5
1, 2, 9, 61, 550, 6195, 83837, 1326923, 24078588, 493309850, 11271757335, 284379843234, 7856320956198, 235986714918110, 7660827258318780, 267365373971139600, 9985779421324740445, 397508459931685273305 (list; graph; listen)
OFFSET

0,2

FORMULA

G.f.: 1 = Sum_{k>=0} a(k)*x^k*(1-x)^((k+2)*(k+3)/2 - 1).

EXAMPLE

1 = 1*(1-x)^2 + 2*x*(1-x)^5 + 9*x^2*(1-x)^9 +

61*x^3*(1-x)^14 + 550*x^4*(1-x)^20 + 6195*x^5*(1-x)^27 +...

PROGRAM

(PARI) {a(n)=polcoeff(1-sum(k=0, n-1, a(k)*x^k*(1-x+x*O(x^n))^((k+2)*(k+3)/2-1)), n)}

CROSSREFS

Cf. A107880, A107881, A107882.

Sequence in context: A036774 A166882 A053983 this_sequence A088182 A006155 A121870

Adjacent sequences: A107880 A107881 A107882 this_sequence A107884 A107885 A107886

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Jun 04 2005

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Last modified December 7 08:40 EST 2009. Contains 170430 sequences.


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