Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 5*b^2.
A216561
Numbers n such that the n-th Fibonacci number is prime, but cannot be written in the form a^2 + 5*b^2.
Terms
- a(0) =3a(1) =4a(2) =5a(3) =7a(4) =13a(5) =17a(6) =23a(7) =43a(8) =47a(9) =83a(10) =137a(11) =433a(12) =4723a(13) =5387a(14) =9677a(15) =30757a(16) =50833a(17) =201107a(18) =931517a(19) =1049897a(20) =1285607a(21) =1636007
External references
- oeis: A216561