Numbers n such that 6*10^n-1 is prime.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =5a(5) =7a(6) =10a(7) =13a(8) =22a(9) =23a(10) =28a(11) =34a(12) =40a(13) =61a(14) =73a(15) =361a(16) =490a(17) =613a(18) =1624a(19) =2000a(20) =2994a(21) =4301a(22) =4332a(23) =18668a(24) =32544a(25) =34936a(26) =267598a(27) =270658a(28) =293134a(29) =319889