Smallest prime p such that n*p+1 is a perfect power, or 0 if no such p exists.

Terms

a(0) =3a(1) =13a(2) =5a(3) =2a(4) =3a(5) =2801a(6) =5a(7) =3a(8) =7a(10) =13a(11) =2a(12) =2a(13) =241a(14) =13a(15) =3a(16) =19a(17) =19a(18) =17a(19) =463a(20) =3a(21) =11a(22) =89a(23) =2a(24) =23a(25) =757a(26) =29a(27) =732541a(28) =31a(29) =917087137a(30) =29