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A066652
Primes of the form 2*s - 1, where s is a squarefree number (A005117).
3
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
1,1
LINKS
EXAMPLE
a(10) = A000040(17) = 59 = 2*30-1 = 2*A005117(19)-1.
MATHEMATICA
Select[2 * Select[Range[200], SquareFreeQ] - 1, PrimeQ] (* Amiram Eldar, Feb 22 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 10 2002
STATUS
approved