go-求阶乘之和

package main
    import "fmt"
    func sum(n int) uint64{
        var s uint64 = 1
        var sum uint64 = 0
        for i := 1; i <= n; i++ {
            s = s * uint64(i)
            sum += s
        }
        return sum
    }
    func main() {
        var n int
        fmt.Scanf("%d",&n)
        s := sum(n)
        fmt.Println(n)
    }