A124408 Numbers k such that 2k+1, 4k+1 and 6k+1 are primes.

1, 3, 18, 105, 135, 153, 165, 168, 300, 363, 585, 618, 648, 765, 828, 1110, 1140, 1278, 1518, 1530, 1533, 2130, 2223, 2400, 2475, 2613, 2790, 2925, 3075, 3180, 3345, 3420, 3483, 3810, 3840, 3843, 3933, 4008, 4083, 4095, 4143, 4260, 4263, 4323, 4470, 4545

Offset

1,2

Links

Jinyuan Wang, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[4600], And @@ PrimeQ /@ ({2, 4, 6}*# + 1) &] (* Ray Chandler, Nov 20 2006 *)

Prog

(PARI) is(k) = sum(j = 1, 3, isprime(2*j*k+1)) == 3; \\ Jinyuan Wang, Aug 04 2019

Crossrefs

Cf. A005097, A005098, A024899, A123998, A124409, A124410, A124411, A071576.

Sequence in context: A327828 A009021 A303519 * A136779 A106328 A007277

Adjacent sequences: A124405 A124406 A124407 * A124409 A124410 A124411

Keyword

nonn

Author

Artur Jasinski, Oct 31 2006

Status

approved