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A356410
Numbers k for which k^3 is divisible by sigma(k).
3
1, 6, 28, 30, 84, 102, 120, 364, 420, 496, 672, 840, 1080, 1092, 1320, 1428, 1488, 1782, 2280, 2716, 2760, 3276, 3360, 3444, 3472, 3480, 3720, 4452, 5640, 7080, 7392, 7440, 7560, 8128, 8148, 8736, 8910, 9240, 9480, 10416, 10920, 11880, 12400, 15456, 15960
OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2000 from Robert Israel)
EXAMPLE
30 is a term, because 30^3 = 27000, sigma(30) = 72 and 27000 / 72 = 375.
MAPLE
select(t -> t^3 mod numtheory:-sigma(t) = 0, [$1..20000]); # Robert Israel, Sep 16 2022
MATHEMATICA
Select[Range[16000], Divisible[#^3, DivisorSigma[1, #]] &]
Select[Range[16000], PowerMod[#, 3, DivisorSigma[1, #]]==0&] (* Harvey P. Dale, Sep 04 2024 *)
PROG
(PARI) for(k=1, 10^6, if(k^3%sigma(k)==0, print1(k, ", "))) \\ Alexandru Petrescu, Sep 10 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Zdenek Cervenka, Aug 05 2022
STATUS
approved