

A072587


Numbers having at least one prime factor with an even exponent.


14



4, 9, 12, 16, 18, 20, 25, 28, 36, 44, 45, 48, 49, 50, 52, 60, 63, 64, 68, 72, 75, 76, 80, 81, 84, 90, 92, 98, 99, 100, 108, 112, 116, 117, 121, 124, 126, 132, 140, 144, 147, 148, 150, 153, 156, 162, 164, 169, 171, 172, 175, 176, 180, 188, 192, 196, 198, 200, 204
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OFFSET

1,1


COMMENTS

Complement of the union of {1} and A002035. [Correction, Nov 15 2012]
The asymptotic density of this sequence is 1  A065463 = 0.2955577990...  Amiram Eldar, Jul 21 2020


LINKS



MATHEMATICA

Select[Range[210], MemberQ[EvenQ[Transpose[FactorInteger[#]][[2]]], True] &] (* Harvey P. Dale, Apr 03 2012 *)


PROG

(Haskell)
a072587 n = a072587_list !! (n1)
a072587_list = tail $ filter (any even . a124010_row) [1..]
(Python)
from itertools import count, islice
from sympy import factorint
def A072587_gen(startvalue=1): # generator of terms
return filter(lambda n:not all(map(lambda m:m&1, factorint(n).values())), count(max(startvalue, 1)))


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



