

A195212


Numbers n for which the exponent of the largest prime factor of n is even.


1



4, 9, 16, 18, 25, 36, 49, 50, 64, 72, 75, 81, 98, 100, 121, 144, 147, 150, 162, 169, 196, 200, 225, 242, 245, 256, 288, 289, 294, 300, 324, 338, 361, 363, 392, 400, 441, 450, 484, 490, 507, 529, 576, 578, 588, 600, 605, 625, 648, 675, 676, 722, 726, 729, 735
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OFFSET

1,1


COMMENTS

What is the density of these numbers? It's clear that lim a(n)/n^2 = 0.


LINKS

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


MATHEMATICA

Select[Range[800], EvenQ[FactorInteger[#][[1, 2]]]&] (* Harvey P. Dale, Jul 22 2013 *)


PROG

(PARI) is(n)=if(n<4, 0, n=factor(n)[, 2]; n[#n]%2==0) \\ Charles R Greathouse IV, Sep 14 2011


CROSSREFS

Contains the squares, A000290, as a subsequence (apart from 0 and 1).
Sequence in context: A104021 A073804 A219364 * A313323 A313324 A015871
Adjacent sequences: A195209 A195210 A195211 * A195213 A195214 A195215


KEYWORD

nonn


AUTHOR

Charles R Greathouse IV, Sep 13 2011


STATUS

approved



