A214195 - OEIS

A214195

Numbers with the number of distinct prime factors a multiple of 3.

1, 30, 42, 60, 66, 70, 78, 84, 90, 102, 105, 110, 114, 120, 126, 130, 132, 138, 140, 150, 154, 156, 165, 168, 170, 174, 180, 182, 186, 190, 195, 198, 204, 220, 222, 228, 230, 231, 234, 238, 240, 246, 252, 255, 258, 260, 264, 266, 270, 273, 276, 280, 282, 285

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OFFSET

1,2

COMMENTS

If GCD(a(n),a(m))=1, then a(n)*a(m) is also in this sequence. - _Enrique Pérez Herrero_, Nov 23 2013

LINKS

Enrique Pérez Herrero, Table of n, a(n) for n = 1..5000

FORMULA

A010872(A001221(a(n))) = 0.

MATHEMATICA

Select[Range[1000], Mod[PrimeNu[#], 3]==0&]

PROG