Numbers k such that 8^k == -1 (mod k-1).

Terms

a(0) =2a(1) =6a(2) =14a(3) =66a(4) =186a(5) =378a(6) =546a(7) =1190a(8) =1470a(9) =2406a(10) =4470a(11) =5250a(12) =7086a(13) =18578a(14) =20166a(15) =25806a(16) =42602a(17) =58590a(18) =69006a(19) =85566a(20) =134946a(21) =137346a(22) =170586a(23) =187838a(24) =206646a(25) =262146a(26) =272610a(27) =285390a(28) =289394a(29) =420210