Numbers k such that 41*10^k - 1 is prime.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =17a(5) =19a(6) =36a(7) =60a(8) =70a(9) =83a(10) =92a(11) =276a(12) =324a(13) =330a(14) =486a(15) =3514a(16) =6062a(17) =10760a(18) =53958a(19) =58920a(20) =101892