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A046053 Total number of prime factors of the repunit R(n)=(10^n-1)/9. 18
0, 0, 1, 2, 2, 2, 5, 2, 4, 4, 4, 2, 7, 3, 4, 6, 6, 2, 9, 1, 7, 7, 7, 1, 10, 5, 6, 7, 8, 5, 13, 3, 11, 6, 6, 7, 12, 3, 3, 6, 11, 4, 15, 4, 11, 10, 6, 2, 13, 4, 10, 8, 9, 4, 14, 8, 12, 6, 8, 2, 20, 7, 5, 14, 15, 7, 15, 3, 10, 6, 12, 2, 18, 3, 7, 12, 6, 8, 16, 6, 15, 13, 7, 3, 22, 7, 8, 10, 15, 5 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

LINKS

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

EXAMPLE

R(6) = 111111 = (3) (7) (11) (13) (37), so a(6) = 5.

CROSSREFS

Cf. A002275. For the number of distinct prime factors see A095370.

Sequence in context: A183413 A183380 A095370 * A080348 A096396 A029662

Adjacent sequences:  A046050 A046051 A046052 * A046054 A046055 A046056

KEYWORD

nonn

AUTHOR

Eric Weisstein (eric(AT)weisstein.com)

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Last modified February 17 02:08 EST 2012. Contains 205978 sequences.