A162966 Union of 1 and nonsquarefree numbers (A013929).

1, 4, 8, 9, 12, 16, 18, 20, 24, 25, 27, 28, 32, 36, 40, 44, 45, 48, 49, 50, 52, 54, 56, 60, 63, 64, 68, 72, 75, 76, 80, 81, 84, 88, 90, 92, 96, 98, 99, 100, 104, 108, 112, 116, 117, 120, 121, 124, 125, 126, 128, 132, 135, 136, 140, 144, 147, 148, 150, 152, 153, 156, 160

Offset: 1

Author

Jaroslav Krizek, Jul 19 2009

Keywords

• nonn
• less

Comments

Or, the natural numbers that are not products of distinct primes. Also, number of prime divisors of n < number of nonprime divisors of n. - Juri-Stepan Gerasimov, Nov 10 2009

Crossrefs

Cf. A013929.

Programs

Mathematica

t = {1}; Do[If[Max[Transpose[FactorInteger[n]][[2]]] > 1, AppendTo[t, n]], {n, 2, 160}]; t (* Jayanta Basu, Apr 30 2013 *)

PARI

is(n)=!issquarefree(n)||n==1 \\ Charles R Greathouse IV, Apr 04 2014