The classic n-queens problem asks for placements of just n mutually non-attacking queens on an n × n board. By adding enough pawns, we can arrange to fill roughly one-quarter of the board with mutually non-attacking queens. How many pawns do we need? We discuss that question for square boards as well as rectangular m × n boards.
Chatham, Doug, "The maximum queen’s problem with pawns" (2016). Faculty Research at Morehead State University. 218.