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Search: id:A112241
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| A112241 |
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Expansion of exp(x/(1-2x-2x^2)). |
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+0
1
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| 1, 1, 5, 49, 601, 9281, 170941, 3662065, 89368049, 2446433281, 74212220341, 2470200090161, 89490288001225, 3504680581915969, 147513939627740141, 6639918363792119281, 318237954786998696161, 16178761263710217424385
(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-bx^2)) has general term n!*sum{i=0..n, sum{j=0..n, a^j*(b/a)^(n-i-j)*C(i+j-1,j)C(j,n-i-j)/i!}}.
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FORMULA
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E.g.f. exp(x/(1-2x-2x^2)); a(n)=n!*sum{i=0..n, sum{j=0..n, 2^j*C(i+j-1, j)C(j, n-i-j)/i!}};
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CROSSREFS
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Sequence in context: A146311 A001079 A081474 this_sequence A116873 A089914 A052142
Adjacent sequences: A112238 A112239 A112240 this_sequence A112242 A112243 A112244
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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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