A066652 Primes of the form 2*s - 1, where s is a squarefree number (A005117).

3, 5, 11, 13, 19, 29, 37, 41, 43, 59, 61, 67, 73, 83, 101, 109, 113, 131, 137, 139, 157, 163, 173, 181, 193, 211, 227, 229, 257, 277, 281, 283, 307, 313, 317, 331, 347, 353, 373, 379, 389, 397, 401, 409, 419, 421, 433, 443, 457

Offset: 1

Author

Reinhard Zumkeller, Jan 10 2002

Keywords

• nonn

Examples

			a(10) = A000040(17) = 59 = 2*30-1 = 2*A005117(19)-1.
		

Links

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

Crossrefs

Cf. A005383, A066651, A066653.

Programs

Mathematica

Select[2 * Select[Range[200], SquareFreeQ] - 1, PrimeQ] (* Amiram Eldar, Feb 22 2021 *)