A252813 Number of n X n nonnegative integer arrays with upper left 0 and every value within 2 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.

1, 6, 63, 684, 7564, 86724, 1033761, 12755742, 161986236, 2106102800, 27918827562, 376114207132, 5136290930902, 70961672284626, 990271326335611, 13940676825684808, 197768062909075426, 2824828311338844486

Offset: 1

Author

R. H. Hardin, Dec 22 2014

Keywords

• nonn

Comments

Diagonal of A252820

Examples

			Some solutions for n=4
..0..0..1..2....0..1..2..3....0..1..1..2....0..1..1..2....0..1..2..2
..0..0..1..2....1..1..2..3....0..1..1..2....1..2..2..3....1..2..2..3
..0..1..2..3....2..2..3..4....0..1..2..3....2..2..3..3....2..2..3..4
..1..2..3..4....2..3..4..4....1..2..3..4....2..3..3..4....3..3..4..5
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..40