a(n) = least odd prime p such that (p^(P(n))-1)/(p-1) is prime with P(i) = i-th prime, n>1.

Terms

a(0) =3a(1) =7a(2) =3a(3) =5a(4) =3a(5) =11a(6) =11a(7) =113a(8) =151a(9) =19a(10) =61a(11) =53a(12) =89a(13) =5a(14) =307a(15) =19a(16) =19a(17) =491a(18) =3a(19) =11a(20) =271a(21) =41a(22) =251a(23) =271a(24) =359a(25) =3a(26) =19a(27) =79a(28) =233a(29) =5