A167207 Numbers that are not divisible by a smaller number that is a square greater than 1.

1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 26, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 46, 47, 49, 51, 53, 55, 57, 58, 59, 61, 62, 65, 66, 67, 69, 70, 71, 73, 74, 77, 78, 79, 82, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 101, 102, 103, 105, 106

Offset: 1

Author

Lee A. Newberg, Oct 30 2009

Keywords

• nonn
• easy

Examples

			14 is a term because there is no square strictly between 1 and 14 that divides 14.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

The union of A005117 (squarefree numbers) and A001248 (squares of primes).

Programs

Mathematica

q[n_] := Module[{e = FactorInteger[n][[;;, 2]]}, e == {2} || AllTrue[e, # == 1 &]]; Select[Range[120], q] (* Amiram Eldar, Jul 02 2025 *)

PARI

isok(n) = {fordiv (n, d, if (issquare(d) && (d>1) && (dMichel Marcus, Jun 08 2013