Numbers k such that 4*k-1, 8*k-1, 16*k-1 and 32*k-1 are all primes.

Terms

a(0) =45a(1) =90a(2) =675a(3) =885a(4) =3030a(5) =4290a(6) =6870a(7) =13410a(8) =14460a(9) =15855a(10) =17850a(11) =18675a(12) =20625a(13) =21885a(14) =25350a(15) =26820a(16) =26925a(17) =28230a(18) =30525a(19) =30705a(20) =31710a(21) =31785a(22) =33375a(23) =34860a(24) =41685a(25) =41940a(26) =57435a(27) =63420a(28) =63570a(29) =71805