Conversion is from 24 bit RGB of this theme into the
256 color Xterm palette. The naive conversion script
obtains e.g. "#d7afaf" as argument and its source-code is:
fromhex () {
local hex r g b
hex=${${1#"#"}#0x}
r="0x${hex[1,2]:-0}"
g="0x${hex[3,4]:-0}"
b="0x${hex[5,6]:-0}"
printf -- '%03d\n' "$(( (r<75?0:(r-35)/40)*6*6 +
(g<75?0:(g-35)/40)*6 +
(b<75?0:(b-35)/40) + 16 ))" | tee >(pbcopy)
}