Numbers k such that k^2 divides 8^k + 1.

Terms

a(0) =1a(1) =3a(2) =9a(3) =57a(4) =171a(5) =32547a(6) =97641a(7) =784899a(8) =9961491a(9) =14913081a(10) =24738057a(11) =29884473a(12) =250537059a(13) =297381939a(14) =892145817a(15) =1338104811a(16) =4014314433a(17) =5688011361a(18) =8515369251a(19) =8920514307a(20) =9146532873a(21) =14125430547a(22) =17064034083a(23) =26761542921a(24) =27439598619a(25) =143056660689a(26) =243640690617a(27) =730922071851