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A039743 GCD(phi(a(n)),a(n)-1) = number of prime factors of a(n). 0
2, 4, 8, 15, 16, 32, 35, 39, 51, 55, 63, 64, 70, 75, 87, 95, 99, 111, 115, 119, 123, 128, 130, 135, 143, 147, 154, 155, 159, 171, 183, 187, 203, 207, 215, 219, 235, 238, 256, 267, 275, 279, 280, 287, 291, 295, 299, 303, 310, 319, 322, 323, 327, 335, 339, 351 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

phi(15)=8, gcd(8,14)=2, 15=3*5, 2 prime factors.

CROSSREFS

Cf. A000010, A001221.

Sequence in context: A072202 A076351 A140117 * A070008 A033623 A094398

Adjacent sequences:  A039740 A039741 A039742 * A039744 A039745 A039746

KEYWORD

nonn,easy

AUTHOR

Olivier Gerard (olivier.gerard(AT)gmail.com)

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Last modified February 13 19:54 EST 2012. Contains 205536 sequences.