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A124408 Numbers k such that 2k+1, 4k+1 and 6k+1 are primes. 6
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 19 11:09 EDT 2019. Contains 328216 sequences. (Running on oeis4.)