I wrote a little applet where you can put in a class A decimal IP address, and it gives you the 3×4 representations mentioned in the article: https://jtvjan.nl/

I wrote a little applet where you can put in a class A decimal IP address, and it gives you the 3×4 representations mentioned in the article: https://jtvjan.nl/tools/cursed_ipv4.html https://jtvjan.nl/tools/cursed_ipv4.html If you count mixed representations, there would be 120 possibilities, but the tool doesn't generate those.