A team has finished a game with 21-20-1 runs-hits-errors line 4 times since 1897, most recently Seattle Mariners on 30 May 2012. That is about one every 110,751 team-games.
Box score for the most recent one ↗
21-17-1 21-17-2 21-18-4 21-18-0 21-19-2 21-19-0 21-20-1 21-20-2 21-20-0 21-21-4 21-21-0 21-22-4 21-22-3
The whole distribution — Runs-Hits-Errors Lines · All 18 shapes