login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A111929 Numerator of x(n) = Sum_{k=1..n} ((odd part of k)/(k^2)). 6
1, 5, 19, 79, 443, 463, 3481, 14029, 44327, 9067, 103769, 104693, 1405361, 1425953, 7321957, 29332873, 510190361, 515635801, 9993116059, 10039674571, 10217040331, 10301692171, 240663600893, 241109786633, 1222682465581 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Denominator of x(n) = A111930(n);

x(n) = a(n)/A111930(n) does not converge.

REFERENCES

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

LINKS

Robert Israel, Table of n, a(n) for n = 1..2296

Eric Weisstein's World of Mathematics, Odd Part

MAPLE

map(numer, ListTools:-PartialSums([seq(1/k/2^padic:-ordp(k, 2), k=1..100)])); # Robert Israel, Dec 28 2017

MATHEMATICA

od[k_] := k/2^IntegerExponent[k, 2];

a[n_] := Sum[od[k]/k^2, {k, 1, n}] // Numerator;

Array[a, 25] (* Jean-François Alcover, Mar 08 2019 *)

CROSSREFS

Cf. A000265, A111918, A111920, A111922, A111930.

Sequence in context: A163609 A149779 A125657 * A146030 A098041 A317131

Adjacent sequences:  A111926 A111927 A111928 * A111930 A111931 A111932

KEYWORD

nonn,frac

AUTHOR

Reinhard Zumkeller, Aug 21 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 27 22:50 EST 2020. Contains 332319 sequences. (Running on oeis4.)