Numbers n for which 2*R_n + 1 is a prime, where R_n = 11...1 is the repunit (A002275) of length n.
A096506
Numbers n for which 2*R_n + 1 is a prime, where R_n = 11...1 is the repunit (A002275) of length n.
Terms
- a(0) =1a(1) =2a(2) =3a(3) =8a(4) =11a(5) =36a(6) =95a(7) =101a(8) =128a(9) =260a(10) =351a(11) =467a(12) =645a(13) =1011a(14) =1178a(15) =1217a(16) =2442a(17) =3761a(18) =3806a(19) =15617a(20) =26459a(21) =63117a(22) =88545a(23) =93497
External references
- oeis: A096506