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A072587
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Numbers having at least one prime factor with an even exponent.
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14
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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
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1,1
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COMMENTS
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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
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LINKS
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MATHEMATICA
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Select[Range[210], MemberQ[EvenQ[Transpose[FactorInteger[#]][[2]]], True] &] (* Harvey P. Dale, Apr 03 2012 *)
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PROG
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(Haskell)
a072587 n = a072587_list !! (n-1)
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)))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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