a(n) = Sum_{1 <= x_1, x_2, ... , x_n <= n} gcd(x_1,x_2, ... ,x_n).

A344525

a(n) = Sum_{1 <= x_1, x_2, ... , x_n <= n} gcd(x_1,x_2, ... ,x_n).

Terms

    a(0) =1a(1) =5a(2) =30a(3) =276a(4) =3165a(5) =47521a(6) =826000a(7) =16843792a(8) =387723045a(9) =10009889889a(10) =285360865350

External references