random.go

package main

import (
	"math/rand"
	"os"
)

const (
	LINES  = 60
	GROUPS = 6
	NUMS   = 5
	SPACE  = 2
)

var buf = []byte("                                        \n")

func main() {
	for i := 0; i < LINES; i++ {
		i := 0 // Shadow top counter
		for j := 0; j < GROUPS; j++ {
			for k := 0; k < NUMS; k++ {
				buf[i+k] = 48 + byte(rand.Intn(10))
			}
			i += NUMS + SPACE
		}
		os.Stdout.Write(buf)
	}
}

Run here - http://play.golang.org/p/ZQXLUCIxkf