A230843 Cubefree numbers which in their canonical prime factorization have mutually distinct exponents.

1, 2, 3, 4, 5, 7, 9, 11, 12, 13, 17, 18, 19, 20, 23, 25, 28, 29, 31, 37, 41, 43, 44, 45, 47, 49, 50, 52, 53, 59, 61, 63, 67, 68, 71, 73, 75, 76, 79, 83, 89, 92, 97, 98, 99, 101, 103, 107, 109, 113, 116, 117, 121, 124, 127, 131, 137, 139, 147, 148, 149, 151, 153, 157, 163, 164, 167, 169, 171

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

q[n_] := Max[(e = FactorInteger[n][[;; , 2]])] < 3 && Length @ Union[e] == Length[e]; Select[Range[200], q] (* Amiram Eldar, Feb 16 2021 *)

Crossrefs

Intersection of A004709 and A130091.

Disjoint union of {1}, A000040, A001248 and A054753.

Sequence in context: A319237 A331230 A258456 * A188551 A045782 A184112

Adjacent sequences: A230840 A230841 A230842 * A230844 A230845 A230846

Keyword

nonn,easy

Author

Gerasimov Sergey, Oct 31 2013

Status

approved