Bash 37 31 27 bytes
This is inspired by the answer by Bruce Forte. That answer only works with IPv4 which means it doesn't work for me. I have rewritten it into a version that (only) works with IPv6:
ip r g b::|awk '$0=$9" "$9'
This is tested on Ubuntu 14.04.5 connected through PPPoE and sinc...
Bash + Core Utils, 43 Bytes
seq $1|tac|factor|awk 'NF==2&&/666/&&$0=$2'
Takes command line argument. Can be quite slow with larger numbers.
Bash + bsd-games package, 35
primes 2 $[$1+1]|grep 666|tac|sed q
Try it online.
Bash 37 31 27 bytes
This is inspired by the answer by Bruce Forte. That answer only works with IPv4 which means it doesn't work for me. I have rewritten it into a version that (only) works with IPv6:
ip r g b::|awk '$0=$9" "$9'
This is tested on Ubuntu 14.04.5 connected through PPPoE and sinc...
