Numbers k that divide 7^k + 6^k.

Terms

a(0) =1a(1) =13a(2) =169a(3) =2197a(4) =28561a(5) =371293a(6) =2684903a(7) =4826809a(8) =34903739a(9) =62748517a(10) =257734633a(11) =453748607a(12) =815730721a(13) =3185696137a(14) =3350550229a(15) =5898731891a(16) =10604499373a(17) =41414049781a(18) =42655053961a(19) =43557152977a(20) =76683514583