Numbers k such that k^3 divides 4^(k^2) - 1.

Terms

a(0) =1a(1) =3a(2) =21a(3) =57a(4) =219a(5) =399a(6) =903a(7) =1533a(8) =2667a(9) =4161a(10) =7077a(11) =17157a(12) =18543a(13) =29127a(14) =32547a(15) =50673a(16) =65919a(17) =74109a(18) =96141a(19) =113799a(20) =114681a(21) =134463a(22) =194691a(23) =227829a(24) =304311a(25) =352317a(26) =383907a(27) =389193a(28) =463071a(29) =516621