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A066669 Numbers n such that Phi[n] = A000010(n) = 2^k*prime for some k >= 0. 4
7, 9, 11, 13, 14, 18, 21, 22, 23, 25, 26, 28, 29, 33, 35, 36, 39, 41, 42, 44, 45, 46, 47, 50, 52, 53, 55, 56, 58, 59, 65, 66, 69, 70, 72, 75, 78, 82, 83, 84, 87, 88, 89, 90, 92, 94, 97, 100, 104, 105, 106, 107, 110, 112, 113, 115, 116, 118, 119, 123, 130, 132, 137, 138 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

7 is here because Phi[7]=6 divided by 2 is prime; 21 is here because Phi[21]=12 divided by 4 is prime; 15 is not here because Phi[15]=8 divided by 8 is not prime.

CROSSREFS

Cf. A000010, A066670-A066673, A065966.

Sequence in context: A161992 A167377 A004169 * A059808 A020742 A193071

Adjacent sequences:  A066666 A066667 A066668 * A066670 A066671 A066672

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Dec 18 2001

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Last modified February 15 20:26 EST 2012. Contains 205852 sequences.