A111881 Numerators of row sums of array of ratios A111879(n,k)/A111880(n,k).

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

Offset: 3

Author

Wolfdieter Lang, Aug 23 2005

Keywords

• nonn
• easy
• frac

Examples

			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

Cf. A111879, A111880.

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

Formula

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