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A230843
Cubefree numbers which in their canonical prime factorization have mutually distinct exponents.
2
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
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
KEYWORD
nonn,easy
AUTHOR
Gerasimov Sergey, Oct 31 2013
STATUS
approved