a(n) = phi(7^n+1), where phi is Euler's totient function (A000010).
A366639
a(n) = phi(7^n+1), where phi is Euler's totient function (A000010).
Terms
- a(0) =1a(1) =4a(2) =20a(3) =168a(4) =1200a(5) =7600a(6) =43200a(7) =407680a(8) =2712832a(9) =19707408a(10) =112560000a(11) =945677920a(12) =6768230400a(13) =47530457728a(14) =271289229120
External references
- oeis: A366639