Numbers k such that 3^k mod k = 3^k mod k^2.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =9a(5) =11a(6) =20a(7) =22a(8) =27a(9) =33a(10) =81a(11) =99a(12) =220a(13) =243a(14) =644a(15) =729a(16) =1220a(17) =2187a(18) =2420a(19) =5060a(20) =6561a(21) =7128a(22) =8368a(23) =13420a(24) =14740a(25) =19683a(26) =23620a(27) =40573a(28) =55660a(29) =59049