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

Terms

a(0) =3a(1) =45a(2) =705a(3) =945a(4) =5295a(5) =5775a(6) =5955a(7) =6450a(8) =8580a(9) =9945a(10) =11175a(11) =12120a(12) =13095a(13) =18000a(14) =18525a(15) =18690a(16) =19710a(17) =22440a(18) =22785a(19) =24960a(20) =30390a(21) =33780a(22) =34335a(23) =37665a(24) =41790a(25) =44460a(26) =52185a(27) =54180a(28) =56175a(29) =57300