a(n) = Sum_{1 <= x_1, x_2, x_3, x_4, x_5 <= n} ( n/gcd(x_1, x_2, x_3, x_4, x_5, n) )^3.

A371491

a(n) = Sum_{1 <= x_1, x_2, x_3, x_4, x_5 <= n} ( n/gcd(x_1, x_2, x_3, x_4, x_5, n) )^3.

Terms

    a(0) =1a(1) =249a(2) =6535a(3) =63737a(4) =390501a(5) =1627215a(6) =5764459a(7) =16316665a(8) =42876109a(9) =97234749a(10) =214357551a(11) =416521295a(12) =815728525a(13) =1435350291a(14) =2551924035a(15) =4177066233a(16) =6975752529a(17) =10676151141a(18) =16983556183a(19) =24889362237a(20) =37670739565a(21) =53375030199a(22) =78310973115a(23) =106629405775

External references