Integers of the form C(2n,n)^2 * Sum_{i=1..n} 1/phi(i).
A066992
Integers of the form C(2n,n)^2 * Sum_{i=1..n} 1/phi(i).
Terms
- a(0) =4a(1) =72a(2) =1000a(3) =14700a(4) =206388a(5) =3201660a(6) =46132944a(7) =690153750
External references
- oeis: A066992