For n >= 1, a(n) is the least k >= 0 such that k^2 + k + 1 is divisible by 2^n - 1 or a(n) = -1 if no such k exists.
A372494
For n >= 1, a(n) is the least k >= 0 such that k^2 + k + 1 is divisible by 2^n - 1 or a(n) = -1 if no such k exists.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =-1a(4) =5a(5) =-1a(6) =19a(7) =-1a(8) =81a(9) =-1a(10) =-1a(11) =-1a(12) =90a(13) =1885a(14) =4799a(15) =-1a(16) =21905a(17) =-1a(18) =69492a(19) =-1a(20) =99206a(21) =-1a(22) =-1a(23) =-1a(24) =585398a(25) =8985436a(26) =32569980a(27) =-1a(28) =-1a(29) =-1
External references
- oeis: A372494