Numbers n such that 8*10^n + 2*R_n + 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
A103076
Numbers n such that 8*10^n + 2*R_n + 5 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =0a(1) =2a(2) =20a(3) =33a(4) =62a(5) =68a(6) =86a(7) =195a(8) =524a(9) =530a(10) =657a(11) =1874a(12) =2198a(13) =62072a(14) =73076
External references
- oeis: A103076