Numbers k such that (61*10^k - 7)/9 is prime.

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =13a(5) =25a(6) =115a(7) =179a(8) =181a(9) =238a(10) =785a(11) =799a(12) =1193a(13) =1730a(14) =1811a(15) =1871a(16) =2116a(17) =2180a(18) =17878a(19) =22093a(20) =30976a(21) =31631a(22) =43271a(23) =52763a(24) =66575