

A304686


Numbers with strictly decreasing prime multiplicities.


2



1, 2, 3, 4, 5, 7, 8, 9, 11, 12, 13, 16, 17, 19, 20, 23, 24, 25, 27, 28, 29, 31, 32, 37, 40, 41, 43, 44, 45, 47, 48, 49, 52, 53, 56, 59, 61, 63, 64, 67, 68, 71, 72, 73, 76, 79, 80, 81, 83, 88, 89, 92, 96, 97, 99, 101, 103, 104, 107, 109, 112, 113, 116, 117, 121
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OFFSET

1,2


LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000


EXAMPLE

10 = 2*5 has prime multiplicities (1,1) so is not in the sequence.
20 = 2*2*5 has prime multiplicities (2,1) so is in the sequence
90 = 2*3*3*5 has prime multiplicities (1,2,1) so is not in the sequence.


MATHEMATICA

Select[Range[200], Greater@@FactorInteger[#][[All, 2]]&]


PROG

(PARI) isok(n) = my(vm = factor(n)[, 2]); vm == vecsort(vm, , 4) && (#vm == #Set(vm)); \\ Michel Marcus, May 17 2018


CROSSREFS

Cf. A001221, A001222, A001597, A005117, A055932, A071365, A112769, A130091, A133808, A133811, A181819, A242031, A304678, A304679, A283050.
Sequence in context: A268375 A048683 A231876 * A085233 A133813 A326836
Adjacent sequences: A304683 A304684 A304685 * A304687 A304688 A304689


KEYWORD

nonn


AUTHOR

Gus Wiseman, May 16 2018


STATUS

approved



