A253010 Number of nX7 nonnegative integer arrays with upper left 0 and lower right its king-move distance away minus 3 and every value increasing by 0 or 1 with every step right, diagonally se or down.

20, 231, 2902, 33533, 309990, 2327062, 14697256, 541365583, 9617848524, 90094114144, 499454404412, 1875291094664, 5288570216780, 12109231279152, 23836473347284, 42007667355832, 68169527721372, 103870860371584

Offset: 1

Author

R. H. Hardin, Dec 25 2014

Keywords

• nonn

Comments

Column 7 of A253011

Examples

			Some solutions for n=6
..0..0..0..0..0..0..0....0..0..0..0..1..1..2....0..0..0..0..0..0..1
..0..0..1..1..1..1..1....0..0..0..1..1..2..2....0..0..0..0..1..1..1
..0..0..1..1..1..1..2....0..0..0..1..1..2..3....0..0..0..1..1..1..2
..0..0..1..1..1..1..2....0..0..0..1..1..2..3....0..0..1..1..1..2..2
..0..1..1..1..2..2..2....0..1..1..1..1..2..3....0..0..1..1..1..2..2
..0..1..2..2..2..3..3....0..1..1..2..2..2..3....0..0..1..1..2..2..3
		

Links

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

Formula

Empirical: a(n) = (774604193792/3)*n^3 - 8398560300416*n^2 + (277091586550828/3)*n - 343375674454152 for n>18