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!)
A111881 Numerators of row sums of array of ratios A111879(n,k)/A111880(n,k). 2
1, 1, 29, 1, 103, 253, 1669, 181, 30791, 849, 452993, 41003, 94949, 421117, 18358463, 446801, 124184839, 30064511, 80932487, 19812817, 211524139, 333707681, 4757207109, 2557825027, 105920383973, 14417396537, 4649180818987 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,3

COMMENTS

The denominators are given in A069220(n), n>=3.

LINKS

Table of n, a(n) for n=3..29.

FORMULA

a(n)= numerator(sum(r(n, k), k=1..phi(n)-1), with phi(n):=A000010(n) (Euler's totient function) and the ratios r(n, k):=A111879(n, k)/A111880(n, k).

EXAMPLE

The ratios a(n)/A069220(n) are: 1/2, 1/3, 29/12, 1/5, 103/20, 253/105, 1669/280, 181/63, 30791/2520, 849/385, ... (see the W. Lang link under A111879.)

CROSSREFS

Sequence in context: A040868 A169980 A040869 * A040833 A040834 A040832

Adjacent sequences:  A111878 A111879 A111880 * A111882 A111883 A111884

KEYWORD

nonn,easy,frac

AUTHOR

Wolfdieter Lang, Aug 23 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 September 17 22:14 EDT 2021. Contains 347489 sequences. (Running on oeis4.)