Numbers k such that (43*10^k - 421)/9 is prime.

Terms

a(0) =2a(1) =5a(2) =7a(3) =8a(4) =11a(5) =13a(6) =25a(7) =26a(8) =61a(9) =82a(10) =131a(11) =289a(12) =377a(13) =547a(14) =845a(15) =929a(16) =1786a(17) =5887a(18) =6562a(19) =10546a(20) =28033a(21) =33493a(22) =150515a(23) =205183