Numbers n such that (10^n + 1)/11 is prime and can be written in the form a^2 + 7*b^2.
A216531
Numbers n such that (10^n + 1)/11 is prime and can be written in the form a^2 + 7*b^2.
Terms
- a(0) =7a(1) =19a(2) =31a(3) =67a(4) =2137a(5) =268207
External references
- oeis: A216531