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A069083
Numbers n such that sigma(n)/tau(n) has denominator 4.
1
8, 40, 72, 104, 136, 200, 232, 296, 328, 360, 384, 392, 424, 488, 520, 584, 648, 680, 712, 776, 808, 872, 904, 936, 968, 1000, 1096, 1160, 1192, 1224, 1256, 1352, 1384, 1408, 1448, 1480, 1544, 1576, 1640, 1768, 1832, 1864, 1920, 1928, 1960, 2048, 2056
OFFSET
1,1
LINKS
FORMULA
n such that A057021(n)=4.
MATHEMATICA
Select[Range[500], Denominator[DivisorSigma[1, #]/DivisorSigma[0, #]] == 4 &] (* Amiram Eldar, Sep 08 2019 *)
PROG
(Magma) [n:n in [1..2100]|Denominator(SumOfDivisors(n)/#Divisors(n)) eq 4]; // Marius A. Burtea, Sep 08 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 05 2002
STATUS
approved