A366681 Number of distinct prime divisors of 11^n - 1.

2, 3, 4, 4, 3, 6, 4, 5, 5, 5, 4, 9, 4, 6, 6, 7, 3, 8, 3, 7, 9, 9, 5, 12, 6, 8, 6, 10, 4, 11, 5, 9, 9, 7, 7, 12, 6, 8, 12, 10, 9, 13, 4, 12, 8, 10, 5, 18, 7, 10, 9, 10, 6, 11, 9, 15, 7, 8, 5, 16, 5, 10, 15, 12, 7, 19, 6, 12, 10, 15, 7, 18, 3, 9, 13, 11, 8, 20

Offset: 1

Author

Sean A. Irvine, Oct 16 2023

Keywords

• nonn

Links

• Max Alekseyev, Table of n, a(n) for n = 1..316

Crossrefs

Cf. A024127, A001221, A274910, A366682, A366683, A366684, A366685.

Cf. A046800, A133801, A102347, A366707.

Programs

PARI

for(n = 1, 100, print1(omega(11^n - 1), ", "))

Formula

a(n) = omega(11^n-1) = A001221(A024127(n)).