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Search: id:A112242
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| A112242 |
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Expansion of exp(x(1+x)/(1-x)). |
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+0
1
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| 1, 1, 5, 25, 169, 1361, 12781, 136585, 1633745, 21594529, 312239701, 4898379641, 82810239865, 1500015354865, 28970936174909, 594083320767721, 12886811207794081, 294742414455540545, 7087332775240107685
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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In general, e.g.f. exp(x(1+ax)/(1-bx)) has general term sum{i=0..n, sum{j=0..n, a^j*b^(n-i-j)*C(i,j)C(n-j-1,n-i-j)*n!/i!}}.
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FORMULA
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E.g.f.: exp(x(1+x)/(1-x); a(n)=sum{i=0..n, sum{j=0..n, C(i, j)C(n-j-1, n-i-j)*n!/i!}};
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MATHEMATICA
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Range[0, 18]!*CoefficientList[ Series[ Exp[x(1-x^2)/(1 - x)^2], {x, 0, 18}], x] - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 23 2007
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CROSSREFS
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Sequence in context: A134007 A125794 A109793 this_sequence A035341 A137383 A049035
Adjacent sequences: A112239 A112240 A112241 this_sequence A112243 A112244 A112245
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Aug 29 2005
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