A186556 Number of (n+1)X4 0..3 arrays with no 2X2 subblock commuting with any of its horizontal and vertical 2X2 subblock neighbors.

60074, 13360840, 2976803436, 663296784123, 147795682647630, 32931888185295104, 7337893459883784628, 1635031754050410331405, 364318292831600934919531, 81177517366244082982029095

Offset: 1

Author

R. H. Hardin Feb 23 2011

Keywords

• nonn

Comments

Column 3 of A186558

Examples

			Some solutions for 3X4
..2..3..0..0....0..1..2..3....3..3..1..2....1..1..3..0....2..3..1..2
..0..1..0..2....0..3..0..2....0..2..3..2....0..2..1..2....0..1..1..1
..0..0..0..2....0..0..0..2....0..0..3..0....0..0..1..3....0..0..2..3
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200