go - Passing closure as function's argument

Question

From this example: https://gobyexample.com/closures If we change:

    fmt.Println(nextInt())
    fmt.Println(nextInt())
    fmt.Println(nextInt())

to

    fmt.Println(intSeq())
    fmt.Println(intSeq())
    fmt.Println(intSeq())

go run will fail with error: ./prog.go:32:5: Println arg intSeq() is a func value, not called

But from this example: https://gobyexample.com/recursion

    fmt.Println(fact(7))

We can call fact(7) function as fmt.Println's argument. Why we have difference?

Answer 1

Waitting for answers