A309941 - OEIS

A309941

Number of prime factors of n^n - 1, counted with multiplicity.

1, 2, 3, 4, 4, 4, 7, 8, 6, 4, 8, 6, 5, 7, 7, 7, 10, 4, 11, 10, 8, 6, 13, 13, 11, 9, 13, 10, 15, 4, 13, 12, 13, 10, 18, 11, 8, 10, 16, 9, 16, 6, 15, 18, 9, 5, 19, 20, 14, 15, 17, 8, 16, 12, 18, 10, 10, 5, 26, 8, 10, 14, 20, 19, 17, 9, 17, 12, 19, 7, 29, 15, 8, 11, 20, 13, 21, 8

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OFFSET

2,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 2..138 (terms 2..126 from Chai Wah Wu)

factordb, Factors of n^n-1.

EXAMPLE

a(3) = 2: 3^3 - 1 = 26 = 2 * 13.

a(5) = 4: 5^5 - 1 = 3124 = 2^2 * 11 * 71.

MATHEMATICA

a[n_] := PrimeOmega[n^n - 1]; Array[a, 45, 2] (* Amiram Eldar, Jul 04 2024 *)

PROG