Numbers k such that k^2 divides 6^k + 1.

Terms

a(0) =1a(1) =7a(2) =203a(3) =1379a(4) =11977a(5) =39991a(6) =2359469a(7) =4780447a(8) =6521291a(9) =6640739a(10) =9904979a(11) =28434413a(12) =189117439a(13) =282046373a(14) =391803601a(15) =941748059a(16) =1308225583a(17) =1677630367a(18) =1951280863a(19) =3524747261a(20) =5601579361a(21) =7033936399a(22) =11157928901a(23) =11580995069a(24) =55563135481a(25) =77185309397a(26) =114689751841a(27) =156382762711a(28) =233252350471a(29) =324021578027