OFFSET
1,3
EXAMPLE
a(6) = 3 (and not 2) as 18 has six divisors though 12 also has 6 divisors. a(8) = 0 as for every prime p > 2 8p has 8 divisors.
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Oct 18 2002
EXTENSIONS
More terms from Sascha Kurz, Jan 21 2003
STATUS
approved