What is the maximum number of squares 8 queens and 8 nightriders can attack on a 16x16 board? Including but still obstructed by occupied squares, what is the maximum number of squares on a 16x16 board that 8 queens and 8 nightriders can collectively attack at least once each? Even if attacking all 256 squares isn't possible, the maximum number still interests me.

I'm unsure what tags to use for this, or if maybe I should've went to the mathematics SE for this one; please suggest additional tags and let me know if this question would better fit the mathematics SE.
It's possible to attack all squares.

Q - queen

N - nightrider

Yellow background - attacked only by a queen

Red background - attacked only by a nightrider

Orange background - attacked by pieces of both types



Queens are placed such that 5 longest diagonals in each direction are attacked.

This can be done with just 6 queens, so 2 are redundant and result in queens attacking queens by diagonals. So 4 queens are attacked by other queens, 4 are not. I added nightriders on the edge of the board such that the missing squares are also attacked. Placing nightriders on the edge doesn't block any of the queens' attacks.

One can also see that the nightriders attacking queens could be placed in other ways, so there is more than one solution. An interesting question would be-how many?

edit. now correct...