Coding Python to make a game similar to Tic-Tac-Toe

[jefsummers]

This sounds a bit different, not quite a typical tic tac toe. The strategy I would choose would be two steps:
1. If the tile that would make your sum 15 is available, pick it and win.
2. Otherwise, pick the tile that would block your opponent from getting 15.
Example, opponent picks 9. You pick 6. Opponent picks 4 (total=13). You pick 2. Opponent picks 5 and is now over 15. You have 8, so you pick 7 and win.