A331203 Numbers k such that k/(digsum(k)) is an integer cube.

1, 2, 3, 4, 5, 6, 7, 8, 9, 72, 243, 320, 486, 512, 640, 704, 832, 960, 1000, 1088, 1125, 2000, 2401, 3000, 3430, 4000, 4116, 4802, 5000, 5145, 5831, 6000, 6174, 6517, 6860, 7000, 7546, 8000, 8575, 8918, 9000, 9216, 9947, 19683, 35152, 35937, 41743, 43940, 46137

Offset

1,2

Comments

If m belongs to the sequence, then 1000*m also belongs to the sequence. - Rémy Sigrist, Jan 12 2020

Links

Table of n, a(n) for n=1..49.

Example

a(11) = 243: 243/(2 + 4 + 3) = 27 = 3^3.
a(12) = 320: 320/(3 + 2 + 0) = 64 = 4^3.

Mathematica

Select[Range[100000], IntegerQ[CubeRoot[#/Total[IntegerDigits[#]]]] &]

Prog

(Magma) [n : n in[1 .. 1000] | IsIntegral((n/(&+Intseq(n)))^(1/3))];
(PARI) is(n) = my (k=n/sumdigits(n)); type(k)==type(42) && ispower(k, 3) \\ Rémy Sigrist, Jan 12 2020

Crossrefs

Cf. A001102, A005349, A007953, A028839, A059094.

Sequence in context: A024662 A153670 A229184 * A302173 A348799 A341909

Adjacent sequences: A331200 A331201 A331202 * A331204 A331205 A331206

Keyword

nonn,base

Author

K. D. Bajpai, Jan 12 2020

Status

approved