OFFSET
0,3
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..225
FORMULA
EXAMPLE
The number of distinct prime divisors of 89 is 1 (prime).
The number of distinct prime divisors of 889 is 2.
The number of distinct prime divisors of 8889 is 2.
MATHEMATICA
Table[PrimeNu[(8*10^(n + 1) + 1)/9], {n, 0, 50}] (* G. C. Greubel, May 16 2017 *)
PROG
(PARI) a(n) = omega((8*10^(n+1)+1)/9); \\ Michel Marcus, Jan 27 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Apr 29 2005
STATUS
approved