Numbers k such that (424*10^k - 1)/9 is prime.

Terms

a(0) =0a(1) =3a(2) =11a(3) =33a(4) =53a(5) =78a(6) =111a(7) =144a(8) =155a(9) =191a(10) =258a(11) =687a(12) =927a(13) =1829a(14) =5406a(15) =11027a(16) =14526a(17) =19758a(18) =20658a(19) =37865a(20) =61770a(21) =87930