Greatest prime divisor of 2*prime(n)-1.

Terms

a(0) =3a(1) =5a(2) =3a(3) =13a(4) =7a(5) =5a(6) =11a(7) =37a(8) =5a(9) =19a(10) =61a(11) =73a(12) =3a(13) =17a(14) =31a(15) =7a(16) =13a(17) =11a(18) =19a(19) =47a(20) =29a(21) =157a(22) =11a(23) =59a(24) =193a(25) =67a(26) =41a(27) =71a(28) =31a(29) =5