A160785 Even squarefree numbers plus 1.

3, 7, 11, 15, 23, 27, 31, 35, 39, 43, 47, 59, 63, 67, 71, 75, 79, 83, 87, 95, 103, 107, 111, 115, 119, 123, 131, 135, 139, 143, 147, 155, 159, 167, 171, 175, 179, 183, 187, 191, 195, 203, 207, 211, 215, 219, 223, 227, 231, 239, 247, 255, 259, 263, 267, 275, 279

Offset: 1

Author

Ben Paul Thurston, May 26 2009

Keywords

• easy
• nonn

Examples

			10 is an even squarefree number, so 11 is in this list.
		

Crossrefs

Cf. A005117.

Programs

Maple

with(numtheory): a := proc (n) if issqrfree(2*n) = true then 2*n+1 else end if end proc: seq(a(n), n = 1 .. 150); # Emeric Deutsch, Jun 20 2009

Formula

a(n) = A039956(n) + 1.

Extensions

More terms from Emeric Deutsch, Jun 20 2009