A124487 Numbers k such that 2*k-1, 4*k-1, 6*k-1 and 8*k-1 are primes.

3, 45, 705, 945, 5295, 5775, 5955, 6450, 8580, 9945, 11175, 12120, 13095, 18000, 18525, 18690, 19710, 22440, 22785, 24960, 30390, 33780, 34335, 37665, 41790, 44460, 52185, 54180, 56175, 57300, 63570, 66990, 67515, 67725, 73335, 74700

Offset: 1

Author

Artur Jasinski, Nov 04 2006

Keywords

• nonn

Links

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

Crossrefs

Cf. A124485-A124492.

Programs

Mathematica

Select[Range[80000], And @@ PrimeQ /@ ({2, 4, 6, 8}*# - 1) &] (* Ray Chandler, Nov 21 2006 *)

Extensions

Extended by Ray Chandler, Nov 21 2006