256 ANSI colors chart

#!/bin/sh
echo_c() { echo -en "\e[38;5;$1m$2\e[0m"; }
for x in $(seq 0 15); do
  for i in $(seq 1 16); do
    echo_c $(( 16 * x + i )) "$(printf "%4d" $(( 16 * x + i )))"
  done
  echo
done