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A124041
Numbers k such that 2*k+1, 4*k+1 and 8*k+1 are primes.
7
9, 39, 165, 219, 249, 309, 414, 534, 639, 765, 1044, 1065, 1089, 1155, 1395, 1509, 1530, 1554, 1590, 1884, 2079, 2115, 2130, 2310, 2319, 2430, 2475, 2709, 2874, 3060, 3105, 3354, 3420, 3684, 3705, 3780, 3819, 4104, 4314, 4554, 4599, 4659, 4869, 5160
OFFSET
1,1
LINKS
MATHEMATICA
Select[3*Range[2000], And @@ PrimeQ /@ ({2, 4, 8}*# + 1) &] (* Ray Chandler, Dec 06 2006 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Nov 02 2006
STATUS
approved