Numbers k such that 6*7^k - 1 is prime.

Terms

a(0) =0a(1) =1a(2) =2a(3) =7a(4) =18a(5) =55a(6) =69a(7) =87a(8) =119a(9) =141a(10) =189a(11) =249a(12) =354a(13) =1586a(14) =2135a(15) =2865a(16) =2930a(17) =4214a(18) =7167a(19) =67485a(20) =74402a(21) =79326a(22) =231349