Primes of the form 40*R_k + 7, where R_k is the repunit (A002275) of length k.
A092480
Primes of the form 40*R_k + 7, where R_k is the repunit (A002275) of length k.
Terms
- a(0) =7a(1) =47a(2) =4447a(3) =4444444447
External references
- oeis: A092480
A092480
Primes of the form 40*R_k + 7, where R_k is the repunit (A002275) of length k.