A069082 Numbers n such that sigma(n)/tau(n) has denominator 3.

4, 9, 12, 25, 28, 52, 63, 75, 76, 84, 108, 117, 121, 124, 148, 156, 171, 172, 175, 180, 196, 228, 243, 244, 268, 279, 289, 292, 316, 325, 333, 363, 364, 372, 387, 388, 396, 412, 436, 441, 444, 475, 508, 516, 525, 529, 532, 549, 556, 588, 603, 604, 628, 652

Offset

1,1

Comments

Numbers such that the denominator of the fraction (sum of the divisors of n) divided by (the number of divisors of n) equals 3. - Harvey P. Dale, Jul 13 2012

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

n such that A057021(n)=3.

Mathematica

Select[Range[700], Denominator[DivisorSigma[1, #]/DivisorSigma[0, #]] == 3&] (* Harvey P. Dale, Jul 13 2012 *)

Prog

(Magma) [n:n in [1..700]|Denominator(SumOfDivisors(n)/#Divisors(n)) eq 3]; // Marius A. Burtea, Sep 08 2019

Crossrefs

Cf. A000005, A000203, A057021.

Sequence in context: A199973 A320925 A212875 * A344415 A297414 A076794

Adjacent sequences: A069079 A069080 A069081 * A069083 A069084 A069085

Keyword

easy,nonn

Author

Benoit Cloitre, Apr 05 2002

Status

approved