

A119251


Positive integers each with exactly 1 unitary prime divisor (i.e., n is included if and only if A056169(n) = 1).


1



2, 3, 5, 7, 11, 12, 13, 17, 18, 19, 20, 23, 24, 28, 29, 31, 37, 40, 41, 43, 44, 45, 47, 48, 50, 52, 53, 54, 56, 59, 61, 63, 67, 68, 71, 73, 75, 76, 79, 80, 83, 88, 89, 92, 96, 97, 98, 99, 101, 103, 104, 107, 109, 112, 113, 116, 117, 124, 127, 131, 135, 136, 137, 139, 147
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OFFSET

1,1


COMMENTS

Also, numbers expressible as the product of a prime and a powerful number not divisible by that prime.  Franklin T. AdamsWatters, Jul 25 2006


LINKS



EXAMPLE

28 has the prime factorization of 2^2 * 7^1. 28 is therefore included in this sequence because there is exactly one prime raised to an exponent of 1 in 28's prime factorization.


MATHEMATICA

Select[Range@147, Count[FactorInteger@#, 1, 2] == 1 &] (* Robert G. Wilson v, Jul 25 2006 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



