a(n) = phi(prime(n)#-1) where phi is the Euler totient function and p# is the product of all the primes from 2 to p inclusive.

A366810

a(n) = phi(prime(n)#-1) where phi is the Euler totient function and p# is the product of all the primes from 2 to p inclusive.

Terms

    a(0) =1a(1) =4a(2) =28a(3) =180a(4) =2308a(5) =30028a(6) =502080a(7) =9458176a(8) =215401680a(9) =6387798300a(10) =200559384576

External references