A375962 Numbers whose product of proper divisors is not a cube.

4, 6, 9, 10, 12, 14, 15, 18, 20, 21, 22, 25, 26, 28, 32, 33, 34, 35, 36, 38, 39, 44, 45, 46, 48, 49, 50, 51, 52, 55, 57, 58, 60, 62, 63, 65, 68, 69, 72, 74, 75, 76, 77, 80, 82, 84, 85, 86, 87, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 106, 108, 111, 112, 115, 116, 117, 118, 119, 120

Offset

1,1

Comments

All the terms are composites.

Links

Stefano Spezia, Table of n, a(n) for n = 1..10000

Example

28 is a term since 1*2*4*7*14 = 784 is not a cube.

Mathematica

Select[Range[120], !IntegerQ[Product[Part[Divisors[#], i], {i, DivisorSigma[0, #]-1}]^(1/3)] &]

Crossrefs

Cf. A000578, A002808 (supersequence), A007956, A027751, A032741.

Complement of A375960.

Sequence in context: A174896 A304634 A377880 * A319240 A331051 A325270

Adjacent sequences: A375959 A375960 A375961 * A375963 A375964 A375965

Keyword

nonn,easy

Author

Stefano Spezia, Sep 04 2024

Status

approved