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A098905 Odd numbers whose number of distinct prime factors is even. 1
15, 21, 33, 35, 39, 45, 51, 55, 57, 63, 65, 69, 75, 77, 85, 87, 91, 93, 95, 99, 111, 115, 117, 119, 123, 129, 133, 135, 141, 143, 145, 147, 153, 155, 159, 161, 171, 175, 177, 183, 185, 187, 189, 201, 203, 205, 207, 209, 213, 215, 217, 219, 221, 225, 235, 237 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

21 is a member of sequence because 21 is odd and number of distinct prime factors of 21 i.e.2 is even.

CROSSREFS

Cf. A001221.

Sequence in context: A070005 A061346 A046388 * A024556 A146166 A056913

Adjacent sequences:  A098902 A098903 A098904 * A098906 A098907 A098908

KEYWORD

easy,nonn

AUTHOR

Shyam Sunder Gupta (guptass(AT)rediffmail.com), Oct 14 2004

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Last modified February 17 12:38 EST 2012. Contains 206021 sequences.