A111921 - OEIS

A111921

Denominator of x(n) = Sum_{k=1..n} ((odd part of k)/(k^4)).

1, 16, 432, 6912, 864000, 864000, 296352000, 4741632000, 128024064000, 128024064000, 170400029184000, 170400029184000, 374368864117248000, 374368864117248000, 14974754564689920, 239596073035038720

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OFFSET

1,2

COMMENTS

Numerator of x(n) = A111920(n);

x(n) = A111920(n)/a(n) -> 14*zeta(3)/15.

REFERENCES

G. Pólya and G. Szegő, Problems and Theorems in Analysis II (Springer 1924, reprinted 1972), Part Eight, Chap. 1, Sect. 6, Problem 50.

LINKS

Table of n, a(n) for n=1..16.

Eric Weisstein's World of Mathematics, Odd Part

Eric Weisstein's World of Mathematics, Apery's constant

Eric Weisstein's World of Mathematics, Riemann Zeta Function

CROSSREFS

Cf. A000265, A002117, A111930, A111919, A111920, A111923.

Sequence in context: A275035 A275140 A274731 * A118994 A223686 A000489

Adjacent sequences: A111918 A111919 A111920 * A111922 A111923 A111924

KEYWORD

nonn,frac,changed

AUTHOR

Reinhard Zumkeller, Aug 21 2005

STATUS

approved