A209734 1/4 the number of (n+1)X7 0..3 arrays with every 2X2 subblock having distinct edge sums.

123480, 6933120, 420545824, 27425792944, 1809791149768, 121396901813560, 8142073013529816, 548770608436244800, 36942499122761432872, 2491439485029085248096, 167889440702169327824712

Offset: 1

Author

R. H. Hardin Mar 12 2012

Keywords

• nonn

Comments

Column 6 of A209736

Examples

			Some solutions for n=4
..3..1..3..1..0..3..3....3..0..1..1..2..2..3....1..1..1..0..1..1..3
..3..2..3..2..2..2..0....2..2..2..3..3..0..3....2..3..2..0..3..2..3
..3..0..3..1..0..1..0....3..0..1..1..2..2..2....1..3..1..0..1..0..1
..2..0..2..1..3..1..3....2..0..2..3..3..0..1....0..2..1..3..3..3..1
..2..3..3..1..0..0..0....1..0..1..1..2..2..2....0..3..1..2..1..2..1
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210