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A118805
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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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1
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1, 2, 11, 106, 1506, 28736, 694719, 20452602, 712529978, 28746803264, 1320665162746, 68164569542628, 3909330000805268, 246855506805662816, 17030177827550184395, 1275139722566251183642, 103032621304705343054010
(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 + 11*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. A118804 (variant).
Sequence in context: A099713 A111535 A088690 * A198001 A207155 A053988
Adjacent sequences: A118802 A118803 A118804 * A118806 A118807 A118808
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KEYWORD
| nonn
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AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), May 02 2006
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