A356410 Numbers k for which k^3 is divisible by sigma(k).

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

Cf. A000578, A000203, A090777.

Sequence in context: A105402 A362805 A145551 * A338125 A259917 A083865

Adjacent sequences: A356407 A356408 A356409 * A356411 A356412 A356413

Keyword

nonn

Author

Zdenek Cervenka, Aug 05 2022

Status

approved