login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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; 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

Eric Weisstein's World of Mathematics, Odd Part

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

CROSSREFS

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

Sequence in context: A180288 A082141 A054615 * A052379 A158798 A062541

Adjacent sequences:  A111916 A111917 A111918 * A111920 A111921 A111922

KEYWORD

nonn,frac

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 21 2005

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 14 20:13 EST 2012. Contains 205663 sequences.