Smallest m>0 such that (2n-1)2^m+1 is prime, or -1 if no such value exists.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =1a(5) =1a(6) =2a(7) =1a(8) =3a(9) =6a(10) =1a(11) =1a(12) =2a(13) =2a(14) =1a(15) =8a(16) =1a(17) =1a(18) =2a(19) =1a(20) =1a(21) =2a(22) =2a(23) =583a(24) =2a(25) =1a(26) =1a(27) =4a(28) =2a(29) =5