Least positive k such that n * k^k + 1 is a prime, or 0 if no such k exists.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =102414a(5) =1a(6) =2a(7) =17a(8) =2a(9) =1a(10) =36a(11) =1a(12) =2a(13) =3a(14) =2a(15) =1a(16) =210a(17) =1a(18) =20a(19) =3a(20) =990a(21) =1a(22) =6a(23) =2a(24) =2a(25) =6a(26) =2a(27) =1