Column number to name as in excel

package main

import (
    "errors"
    "fmt"
)

func main() {

    for cm := 1; cm < 100; cm++ {
        cmName, _ := ColumnNumberToName(cm)
        fmt.Println(cmName)
    }

}

func ColumnNumberToName(num int) (string, error) {
    if num < 1 {
        return "", fmt.Errorf("incorrect column number %d", num)
    }
    if num > 16384 {
        return "", errors.New("column number exceeds maximum limit")
    }
    var col string
    for num > 0 {
        col = string(rune((num-1)%26+65)) + col
        num = (num - 1) / 26
    }
    return col, nil
}