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A087022 Total number of prime factors of n-th cyclic number. 0
6, 9, 12, 10, 11, 9, 11, 23, 25, 25, 22, 18, 19, 15, 14, 38, 35, 24, 28, 25, 27, 21, 17, 38, 44, 27, 43, 16, 16, 23, 42, 35, 37, 30, 29, 14, 23, 62, 41, 51, 28, 26 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A004042(n) factorized with Dario Alpern's ECM.

Extended using factors of 10^(A001913(n)-1)-1, see Kamada link.

LINKS

Table of n, a(n) for n=1..42.

Dario A. Alpern, Factorization using the Elliptic Curve Method.

Makoto Kamada, Factorizations of 11...11 (Repunit)

Eric Weisstein's World of Mathematics, Cyclic Number

FORMULA

a(n) = A001222(A004042(n+1)).

EXAMPLE

A004042(2) = 142857 = 37*13*11*3^3, therefore a(1) = A087021(1)+2 = 6.

CROSSREFS

Cf. A001913, A087020-A087026.

Sequence in context: A125971 A322158 A143710 * A315951 A081392 A225868

Adjacent sequences:  A087019 A087020 A087021 * A087023 A087024 A087025

KEYWORD

nonn,more,hard

AUTHOR

Reinhard Zumkeller, Jul 30 2003

EXTENSIONS

a(3) corrected, a(12)-a(42) added by Ray Chandler, Nov 16 2011

STATUS

approved

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Last modified May 20 12:33 EDT 2019. Contains 323422 sequences. (Running on oeis4.)