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A279457
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Numbers n such that number of distinct primes dividing n is odd and number of prime divisors (counted with multiplicity) of n is odd.
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4
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2, 3, 5, 7, 8, 11, 13, 17, 19, 23, 27, 29, 30, 31, 32, 37, 41, 42, 43, 47, 53, 59, 61, 66, 67, 70, 71, 73, 78, 79, 83, 89, 97, 101, 102, 103, 105, 107, 109, 110, 113, 114, 120, 125, 127, 128, 130, 131, 137, 138, 139, 149, 151, 154, 157, 163, 165, 167, 168, 170, 173, 174, 179, 180, 181, 182, 186, 190, 191, 193, 195, 197, 199, 211
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OFFSET
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1,1
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COMMENTS
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All primes (A000040) are included in the sequence.
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LINKS
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EXAMPLE
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27 is in the sequence because 27 = 3^3 therefore omega(27) = 1 {3} is odd and bigomega(27) = 3 {3,3,3} is odd.
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MATHEMATICA
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Select[Range[220], Mod[PrimeNu[#1], 2] == Mod[PrimeOmega[#1], 2] == 1 & ]
Select[Range[300], AllTrue[{PrimeNu[#], PrimeOmega[#]}, OddQ]&] (* Harvey P. Dale, Jul 10 2023 *)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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