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A111919 Denominator of x(n) = Sum((odd part of k)/(k^3): 1<=k<=n). 5
1, 8, 72, 576, 14400, 1600, 78400, 627200, 50803200, 50803200, 6147187200, 6147187200, 1038874636800, 1038874636800, 1038874636800, 8310997094400, 2401878160281600, 266875351142400, 96342001762406400, 96342001762406400 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numerator of x(n) = A111918(n);

x(n) = A111918(n)/a(n) ---> Pi*Pi/7 = 6*zeta(2)/7.

REFERENCES

G. Polya and G. Szego, 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..20.

Eric Weisstein's World of Mathematics, Odd Part

Eric Weisstein's World of Mathematics, Riemann Zeta Function zeta(2)

CROSSREFS

Cf. A000265, A013661, A111930, A111921, A111923.

Sequence in context: A304826 A270241 A054615 * A052379 A246940 A158798

Adjacent sequences:  A111916 A111917 A111918 * A111920 A111921 A111922

KEYWORD

nonn,frac

AUTHOR

Reinhard Zumkeller, Aug 21 2005

STATUS

approved

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Last modified August 22 00:43 EDT 2019. Contains 326169 sequences. (Running on oeis4.)