Factorials w/ big numbers in go

fact.go

package main

import (
	"fmt"
	"math/big"
	"time"
)

func fact(n *big.Int) (result *big.Int) {
	b := big.NewInt(0)
	c := big.NewInt(1)

	if n.Cmp(b) == -1 {
		result = big.NewInt(1)
	}

	if n.Cmp(b) == 0 {
		result = big.NewInt(1)

	} else {
		result = new(big.Int)
		result.Set(n)
		result.Mul(result, fact(n.Sub(n, c)))
	}

	return result
}

func main() {

	var startTime = time.Now()
	ch := make(chan *big.Int)
	go func() {
		for i := 0; i < 500	; i++ {

			n := big.NewInt(5000)
			ch <- fact(n)

		} // fmt.Println(fact(n))
	}()

	var wg sync.WaitGroup
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()
		for i := 0; i < 500; i++ {
			<-ch
		}
	}(&wg)

	wg.Wait()

	fmt.Println("CONSUMED: ", time.Now().Sub(startTime))
}