A087023 Maximal exponent in prime factorization of n-th cyclic number.

3, 2, 4, 2, 2, 2, 2, 3, 3, 5, 2, 2, 2, 2, 2, 4, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 5, 2, 2, 2, 5, 2, 7, 2, 3, 2, 2, 5, 3, 4, 2, 3, 2, 2, 2, 3, 3, 2, 6, 2, 3

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..51.

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) = A051903(A004042(n+1)).

Example

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

Crossrefs

Cf. A001913, A087020, A087021, A087022, A087024, A087025, A087026.

Sequence in context: A139583 A073314 A144808 * A328052 A089214 A057038

Adjacent sequences: A087020 A087021 A087022 * A087024 A087025 A087026

Keyword

nonn,more,hard

Author

Reinhard Zumkeller, Jul 30 2003

Extensions

a(12)-a(42) from Ray Chandler, Nov 16 2011

a(43)-a(51) from Max Alekseyev, May 14 2022

Status

approved