Numbers k such that 4*k-1, 8*k-1 and 16*k-1 are all primes.

Terms

a(0) =3a(1) =45a(2) =90a(3) =180a(4) =255a(5) =258a(6) =363a(7) =378a(8) =453a(9) =483a(10) =615a(11) =675a(12) =705a(13) =873a(14) =885a(15) =978a(16) =1350a(17) =1533a(18) =1770a(19) =1788a(20) =2673a(21) =2793a(22) =2868a(23) =3030a(24) =3225a(25) =3240a(26) =4203a(27) =4290a(28) =4548a(29) =4830