Least k such that (n^k+1)/(n+1) is prime, or 0 if no such prime exists.

Terms

a(0) =3a(1) =3a(2) =3a(3) =5a(4) =3a(5) =3a(6) =0a(7) =3a(8) =5a(9) =5a(10) =5a(11) =3a(12) =7a(13) =3a(14) =3a(15) =7a(16) =3a(17) =17a(18) =5a(19) =3a(20) =3a(21) =11a(22) =7a(23) =3a(24) =11a(25) =0a(26) =3a(27) =7a(28) =139a(29) =109