Numbers k such that 7^k + 5^k - 1 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =9a(4) =13a(5) =25a(6) =26a(7) =63a(8) =73a(9) =435a(10) =2245a(11) =2907a(12) =3089a(13) =5615a(14) =20113a(15) =20355a(16) =34127a(17) =47965