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

1,2

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)).

Links

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

Example

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

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 *)

Crossrefs

Cf. A001221, A014612.

Sequence in context: A222656 A162545 A162544 * A083647 A364332 A346389

Adjacent sequences: A209320 A209321 A209322 * A209324 A209325 A209326

Keyword

nonn

Author

Wesley Ivan Hurt, Jan 19 2013

Status

approved