OFFSET
0,3
COMMENTS
Number of distinct prime factors of (10^(n + 1) - 1)/3 + 4. - Stefan Steinerberger, Mar 06 2006
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..199
FORMULA
EXAMPLE
The number of distinct prime divisors of 37 is 1 (prime).
The number of distinct prime divisors of 337 is 1 (prime).
The number of distinct prime divisors of 3337 is 2.
MATHEMATICA
Table[Length[FactorInteger[(10^(n + 1) - 1)/3 + 4]], {n, 1, 50}] (* Stefan Steinerberger, Mar 06 2006 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Apr 18 2005
EXTENSIONS
More terms from Stefan Steinerberger, Mar 06 2006
More terms from Amiram Eldar, Jan 24 2020
STATUS
approved