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Search: id:A152762
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| 0, 0, 1, 1, 10, 54, 204, 243, 1594, 4210, 18484, 62174, 275828, 1131980, 7434360, 10522755, 72469530, 268486410, 1442238420, 4284331050, 18146556060, 62021100660, 248289237960, 798007353390, 2832660378756, 11922780597588
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OFFSET
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0,5
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FORMULA
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a(n) = A001065(A000108(n)).
a(n)=sigma(binom(2n,n)/(n+1)) - binom(2n,n)/(n+1), where sigma(m) is the sum of the divisors of m. [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2008]
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EXAMPLE
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a(4)=10 because the proper divisors of A000108(4)=14 are 1,2 and 7. [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2008]
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MAPLE
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with(numtheory): seq(sigma(binomial(2*n, n)/(n+1))-binomial(2*n, n)/(n+1), n = 0 .. 27); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2008]
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CROSSREFS
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Cf. A000108, A000203, A001065, A152761, A152763.
Sequence in context: A006889 A007035 A093187 this_sequence A053347 A036600 A058645
Adjacent sequences: A152759 A152760 A152761 this_sequence A152763 A152764 A152765
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KEYWORD
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easy,nonn
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AUTHOR
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Omar E. Pol (info(AT)polprimos.com), Dec 14 2008
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 24 2008
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