Nonprimes k such that 3^k == 3 (mod k).

Terms

a(0) =1a(1) =6a(2) =66a(3) =91a(4) =121a(5) =286a(6) =561a(7) =671a(8) =703a(9) =726a(10) =949a(11) =1105a(12) =1541a(13) =1729a(14) =1891a(15) =2465a(16) =2665a(17) =2701a(18) =2821a(19) =3281a(20) =3367a(21) =3751a(22) =4961a(23) =5551a(24) =6601a(25) =7107a(26) =7381a(27) =8205a(28) =8401a(29) =8646