a(n) = phi(5^n-1), where phi is Euler's totient function (A000010).
A295502
a(n) = phi(5^n-1), where phi is Euler's totient function (A000010).
Terms
- a(0) =2a(1) =8a(2) =60a(3) =192a(4) =1400a(5) =4320a(6) =39060a(7) =119808a(8) =894240a(9) =2912000a(10) =24414060a(11) =62208000a(12) =610351560a(13) =1959874560a(14) =13154400000a(15) =44043337728a(16) =380537036928a(17) =997843069440
External references
- oeis: A295502