A244669 Denominators of (product of divisors of n / sum of divisors of n).

1, 3, 4, 7, 6, 1, 8, 15, 13, 9, 12, 7, 14, 6, 8, 31, 18, 13, 20, 21, 32, 9, 24, 5, 31, 21, 40, 1, 30, 1, 32, 63, 16, 27, 48, 91, 38, 15, 56, 9, 42, 2, 44, 21, 26, 18, 48, 31, 57, 93, 8, 49, 54, 5, 72, 15, 80, 45, 60, 7, 62, 24, 104, 127, 84, 1, 68, 63, 32, 9

Offset

1,2

Comments

Denominators of (A007955(n) / A000203(n)).

For numerators see A244668.

Links

Table of n, a(n) for n=1..70.

Formula

a(n) = 1 for numbers from A145551 (numbers n such that product of divisors of n / sum of divisors of n is an integer).

Example

a(8) = 15 because A007955(8) / A000203(8) = 64 / 15.

Prog

(Magma)[Denominator((&*[d: d in Divisors(n)]) / (&+[d: d in Divisors(n)])): n in [1..1000]]
(PARI) a007955(n)=if(issquare(n, &n), n^numdiv(n^2), n^(numdiv(n)/2)) ;
a(n) = denominator(a007955(n)/sigma(n)); \\ Michel Marcus, Jul 05 2014

Crossrefs

Cf. A007955, A000203, A145551, A244668, A244670.

Sequence in context: A299693 A134688 A077650 * A316570 A105853 A277216

Adjacent sequences: A244666 A244667 A244668 * A244670 A244671 A244672

Keyword

nonn,frac

Author

Jaroslav Krizek, Jul 04 2014

Status

approved