I loved this. Found it tough though. I started it last night, made slow progress, picked it up this morning and have only just finished it now. I wasn’t helped by getting the wrong answer for 2, which messed me up for 13, but my answer for 2 doesn’t parse, so my fault. When will I learn?
FOI 3, LOI 5 (can anyone help with the parsing there?). Lots of COD candidates, but I’ll go with 20.
Many thanks to Picaroon, and thanks also to geeker for starting the thread.