A224028 Number of 6Xn 0..3 arrays with rows nondecreasing and antidiagonals unimodal.

4096, 1000000, 30756756, 403836633, 3491241557, 23151623729, 126168072638, 589287463547, 2427724545612, 9007001464858, 30566042176352, 96033091778636, 282028543897612, 780257746938799, 2046679053764299, 5117642427934938

Offset: 1

Author

R. H. Hardin Mar 30 2013

Keywords

• nonn

Comments

Row 6 of A224024

Examples

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

Links

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

Formula

Empirical: a(n) = (42587101/1600593426432000)*n^18 + (23341517/16167610368000)*n^17 + (15783371/356638464000)*n^16 + (31606091/33965568000)*n^15 + (17663092277/1207084032000)*n^14 + (133630090943/747242496000)*n^13 + (3090381263819/1810626048000)*n^12 + (861240248921/67060224000)*n^11 + (16435251844841/219469824000)*n^10 + (3455775661663/10450944000)*n^9 + (654929669980007/603542016000)*n^8 + (1738593710779/653184000)*n^7 + (82071435647381/16717428000)*n^6 + (429177771626699/59439744000)*n^5 - (15320544442081/40864824000)*n^4 - (2761354550633/92664000)*n^3 - (36294722496521/593762400)*n^2 + (776634903133/6126120)*n + 95040 for n>4