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

Terms

a(0) =2a(1) =3a(2) =12a(3) =15a(4) =42a(5) =45a(6) =87a(7) =117a(8) =120a(9) =147a(10) =210a(11) =330a(12) =477a(13) =507a(14) =612a(15) =705a(16) =780a(17) =792a(18) =945a(19) =1002a(20) =1065a(21) =1170a(22) =1275a(23) =1347a(24) =1470a(25) =1680a(26) =1695a(27) =1797a(28) =1902a(29) =2175