A337502 Minimum number of painted cells in an n X n grid to avoid unpainted tetrominoes.

0, 1, 3, 6, 9, 15, 20, 27, 34, 43

Offset: 1

Author

Rob Pratt, Aug 29 2020

Keywords

• nonn
• more

Examples

			For n = 4, painting only 5 cells would leave an unpainted tetromino, but painting the following 6 cells avoids all unpainted tetrominoes:
. . X .
X X . X
. . X .
. X . .
		

Crossrefs

Cf. A337501.