A250693 Number of (2+1)X(n+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

520, 2920, 13906, 60508, 249512, 995624, 3894542, 15061244, 57914756, 222291368, 853854042, 3287692860, 12701872800, 49262782920, 191821043814, 749801489244, 2941369935292, 11575782602248, 45685412767666, 180742482085084

Offset: 1

Author

R. H. Hardin, Nov 26 2014

Keywords

• nonn

Comments

Row 2 of A250691

Examples

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

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -175*a(n-2) +882*a(n-3) -2835*a(n-4) +6072*a(n-5) -8777*a(n-6) +8458*a(n-7) -5204*a(n-8) +1848*a(n-9) -288*a(n-10)