a(n) = phi(12^n-1), where phi is Euler's totient function (A000010).

A366711

a(n) = phi(12^n-1), where phi is Euler's totient function (A000010).

Terms

    a(0) =10a(1) =120a(2) =1560a(3) =13440a(4) =226200a(5) =2021760a(6) =32518360a(7) =274391040a(8) =4534807680a(9) =51953616000a(10) =646094232960

External references