0,4

Also number of distinct prime factors of 6/9*(10^(n + 1) - 1) - 5. - Stefan Steinerberger, Feb 26 2006

Table of n, a(n) for n=0..49.

Number of distinct prime divisors of 61 is 1 (prime).

Number of distinct prime divisors of 661 is 1 (prime).

Number of distinct prime divisors of 6661 is 1 (prime).

Table[Length[FactorInteger[6/9*(10^(n + 1) - 1) - 5]], {n, 1, 50}] (* Stefan Steinerberger, Feb 26 2006 *)

Cf. A104564.

Sequence in context: A067279 A106267 A096101 * A064123 A024703 A102845

Adjacent sequences: A104887 A104888 A104889 * A104891 A104892 A104893

nonn

Parthasarathy Nambi, Apr 24 2005

More terms from Stefan Steinerberger, Feb 26 2006

approved