A209323 Values of omega(n) (A001221) as n runs through the triprimes (A014612).

1, 2, 2, 2, 1, 2, 3, 3, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 3, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 1, 3, 3, 2, 2, 2, 3, 2, 3, 3, 2, 2, 3, 2, 3, 3, 2, 3, 3, 2, 2, 3, 3, 3, 2, 3, 2, 2, 2, 3, 3, 3, 2, 3, 2, 3, 2, 2, 3, 2, 3, 3, 3, 2, 3, 2, 3, 3, 2, 2, 2, 2, 1, 3, 3, 2, 3, 2

Offset: 1

Author

Wesley Ivan Hurt, Jan 19 2013

Keywords

• nonn

Comments

omega(n) is the number of distinct prime divisors of n. A number is triprime if it has exactly 3 (not necessarily distinct) prime divisors.

a(n) = omega(A014612(n)).

Examples

			First triprime = 8, has 1 distinct prime divisor (2) so a(1) = 1.
		

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001221, A014612.

Programs

Mathematica

t = {}; Do[f = FactorInteger[n]; If[Total[Transpose[f][[2]]] == 3, AppendTo[t, Length[f]]], {n, 400}]; t (* T. D. Noe, Jan 23 2013 *)