Smallest prime p such that (p-1) has n divisors, or 0 if no such prime exists.

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =17a(5) =13a(6) =0a(7) =31a(8) =37a(9) =113a(10) =0a(11) =61a(12) =0a(13) =193a(14) =401a(15) =211a(16) =65537a(17) =181a(18) =0a(19) =241a(20) =577a(21) =13313a(22) =0a(23) =421a(24) =1297a(25) =12289a(26) =4357a(27) =2113a(28) =0a(29) =1009