GoLang Tour - Fibonacci Closure exercise

package main

import "fmt"
import "math"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func(int) int {
  return func(x int) int {
    // Use the Golden ratio formula to calculate the fibonacci value given an integer
    // position. (i.e position 6 == value of 8)
    //
    // http://sahandsaba.com/five-ways-to-calculate-fibonacci-numbers-with-python-code.html
    a := math.Pow(1.618034, float64(x))
    b := math.Pow((1 - 1.618034), float64(x))
    y := (a - b) / math.Sqrt(float64(5))
    return int(y)
  }
}

func main() {
	f := fibonacci()
	for i := 0; i < 10; i++ {
		fmt.Println(f(i))
	}
}