Smallest k such that k*n+1 is prime.

Terms

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