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A118804
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G.f.: 1 = Sum_{n>=0} a(n)*x^n/Prod_{k=1..n} (1-k*x)^2.
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4
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1, -2, 9, -66, 685, -9294, 156697, -3169910, 74998081, -2035262154, 62391632417, -2134187066010, 80641239109677, -3337651407273846, 150239268816661137, -7310140430519234862, 382439924662714479457, -21413128578896024921298, 1277905479699750127195097
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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EXAMPLE
| 1 = 1/(1-x)^2 - 2*x/[(1-x)(1-2x)]^2 + 9*x^2/[(1-x)(1-2x)(1-3x)]^2 + ...
+ a(n)*x^n/[(1-x)(1-2x)(1-3x)...(1-n*x)]^2 +...
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PROG
| (PARI) {a(n)=if(n==0, 1, polcoeff(1-sum(k=0, n-1, a(k)*x^k*prod(j=1, k+1, 1-j*x+x*O(x^n))^-2), n))}
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CROSSREFS
| Cf. A118805 (variant).
Sequence in context: A152213 A089471 A196193 * A020555 A091795 A158952
Adjacent sequences: A118801 A118802 A118803 * A118805 A118806 A118807
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KEYWORD
| sign
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AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), May 02 2006
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