Numbers k such that 8*10^k-1 is prime.

Terms

a(0) =0a(1) =1a(2) =4a(3) =5a(4) =8a(5) =10a(6) =25a(7) =49a(8) =76a(9) =128a(10) =175a(11) =238a(12) =550a(13) =796a(14) =1219a(15) =2012a(16) =2846a(17) =11336a(18) =21296a(19) =49808a(20) =74318a(21) =236891a(22) =608989a(23) =1652593a(24) =1715905a(25) =1990324a(26) =2045966a(27) =2084563a(28) =5112847