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Search: id:A112243
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| A112243 |
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Expansion of exp(x(1+x)/(1-2x)). |
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+0
1
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| 1, 1, 7, 55, 577, 7441, 113671, 2003527, 39971905, 889608097, 21834577351, 585555975511, 17027451783937, 533460597334705, 17908302027585607, 641152804988733031, 24380543011087797121, 981149507717921468737
(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)/(1-2x); 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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CROSSREFS
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Sequence in context: A091695 A002882 A094905 this_sequence A083836 A159313 A054910
Adjacent sequences: A112240 A112241 A112242 this_sequence A112244 A112245 A112246
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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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