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

Terms

a(0) =5a(1) =7a(2) =17a(3) =19a(4) =71a(5) =11a(6) =23a(7) =109a(8) =37a(9) =449a(10) =191a(11) =379a(12) =881a(13) =101a(14) =83a(15) =521a(16) =257a(17) =227a(18) =41a(19) =2591a(20) =31a(21) =149a(22) =1231a(23) =83a(24) =79a(25) =743a(26) =29a(27) =17a(28) =3079a(29) =41