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A111930
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Denominator of x(n) = Sum_{k=1..n} ((odd part of k)/(k^2)).
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6
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1, 4, 12, 48, 240, 240, 1680, 6720, 20160, 4032, 44352, 44352, 576576, 576576, 2882880, 11531520, 196035840, 196035840, 3724680960, 3724680960, 3724680960, 3724680960, 85667662080, 85667662080, 428338310400, 428338310400
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OFFSET
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1,2
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COMMENTS
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x(n) = A111929(n)/a(n) does not converge.
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REFERENCES
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G. Pólya and G. Szegő, Problems and Theorems in Analysis I (Springer 1924, reprinted 1972), Part Eight, Chap. 1, Sect. 6, Problem 50.
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LINKS
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Eric Weisstein's World of Mathematics, Odd Part
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MAPLE
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map(denom, ListTools:-PartialSums([seq(1/k/2^padic:-ordp(k, 2), k=1..100)])): # Robert Israel, Dec 28 2017
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MATHEMATICA
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od[k_] := k/2^IntegerExponent[k, 2];
a[n_] := Sum[od[k]/k^2, {k, 1, n}] // Denominator;
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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