Numbers k such that k^2 divides 13^k - 1.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =12a(6) =14a(7) =20a(8) =28a(9) =42a(10) =60a(11) =68a(12) =84a(13) =140a(14) =183a(15) =204a(16) =220a(17) =340a(18) =366a(19) =406a(20) =420a(21) =476a(22) =660a(23) =732a(24) =812a(25) =942a(26) =1020a(27) =1218a(28) =1428a(29) =1540