A124493 Numbers k for which 2*k-1, 4*k-1 and 8*k-1 are primes.

3, 6, 21, 45, 90, 180, 255, 360, 510, 516, 615, 705, 726, 741, 756, 906, 945, 951, 966, 1230, 1350, 1410, 1725, 1746, 1770, 1911, 1956, 2541, 2700, 2721, 2925, 3051, 3066, 3225, 3540, 3576, 3675, 3951, 4485, 4611, 5295, 5346, 5355, 5586, 5736, 5775, 5901

Offset

1,1

Links

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

Mathematica

Select[3*Range[2000], And @@ PrimeQ /@ ({2, 4, 8}*# - 1) &] (* Ray Chandler, Nov 22 2006 *)

Crossrefs

Cf. A006254, A124485, A124494, A124017, A125113, A124514, A124515, A124516.

Sequence in context: A327890 A076102 A094282 * A136331 A063683 A200380

Adjacent sequences: A124490 A124491 A124492 * A124494 A124495 A124496

Keyword

nonn

Author

Artur Jasinski, Nov 04 2006

Status

approved