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A112243
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Expansion of exp(x(1+x)/(1-2x)).
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0
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1, 1, 7, 55, 577, 7441, 113671, 2003527, 39971905, 889608097, 21834577351, 585555975511, 17027451783937, 533460597334705, 17908302027585607, 641152804988733031, 24380543011087797121, 981149507717921468737
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| 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
| E.g.f.: exp(x(1+x)/(1-2x); a(n)=sum{i=0..n, sum{j=0..n, 2^(n-i-j)*C(i, j)C(n-j-1, n-i-j)*n!/i!}};
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MATHEMATICA
| With[{nn=20}, CoefficientList[Series[Exp[(x(x+1))/(1-2x)], {x, 0, nn}], x] Range[0, nn]!] (* From Harvey P. Dale, Sep 21 2011 *)
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CROSSREFS
| Sequence in context: A002882 A094905 A178922 * A083836 A159313 A054910
Adjacent sequences: A112240 A112241 A112242 * A112244 A112245 A112246
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Aug 29 2005
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