#!/bin/bash
for i in {0..255}; do printf "\e[38;5;${i}m%4d " $i; ((i%16==15)) && echo ""; done; echo -e "\e[0m"

echo -e -n "\e[38;5;243m"
echo  "Use these colors with \\e[38;5;<number>m<message>\\e[0m"
echo -e -n "\e[0m"