http://tantek.pbworks.com/w/page/19402946/NewBase60 Got the idea from here.

new-base-60.go

package main

import (
    "time"
    "strconv"
    "fmt"
)

var NewBase60Vocab [60]string

func init() {
    NewBase60Vocab = [60]string{ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "J", "K", "L", "M", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "_", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" }
}


func main() {
    now := time.Now()
    count     := strconv.Itoa(11)
    dayOfYear := strconv.Itoa(now.YearDay())
    year      := strconv.Itoa(now.Year())

    dateCount, _ := strconv.Atoi(year + dayOfYear + count)
    sgx := ""
    for dateCount > 0 {
        mod := dateCount % 60
        sgx = sgx + NewBase60Vocab[mod]
        dateCount = (dateCount - mod)/60
    }
    fmt.Println(sgx)
}