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A069081 Numbers n such that sigma(n)/tau(n) has denominator 2. 3
2, 10, 18, 24, 26, 32, 34, 50, 58, 74, 82, 88, 90, 98, 106, 120, 122, 130, 146, 152, 160, 170, 178, 194, 202, 216, 218, 226, 234, 242, 250, 274, 288, 290, 298, 306, 312, 314, 338, 344, 346, 362, 370, 386, 394, 408, 410, 416, 440, 442, 458, 466, 472, 482, 490 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
n such that A057021(n)=2.
MATHEMATICA
Select[Range[500], Denominator[DivisorSigma[1, #]/DivisorSigma[0, #]] == 2 &] (* Amiram Eldar, Sep 08 2019 *)
PROG
(Magma) [n:n in [1..500]|Denominator(SumOfDivisors(n)/#Divisors(n)) eq 2]; // Marius A. Burtea, Sep 08 2019
CROSSREFS
Sequence in context: A341032 A082939 A074069 * A126005 A017089 A097269
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 05 2002
STATUS
approved

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Last modified April 17 11:20 EDT 2024. Contains 371763 sequences. (Running on oeis4.)