A224171 Number of n X 6 0..3 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

610, 52591, 1253770, 15925611, 143558572, 1038484760, 6360047093, 33901838632, 160168789130, 680269560125, 2628521964178, 9335303943077, 30746296739238, 94635507313740, 274045375789233, 750986358734170, 1957473961121912, 4874764357410065, 11644219526875714

Offset: 1

Author

R. H. Hardin, Mar 31 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 6 of A224173.

Formula

Empirical: a(n) = (42587101/1600593426432000)*n^18 + (83940121/177843714048000)*n^17 + (308341547/31384184832000)*n^16 + (23656547/201180672000)*n^15 + (19255277651/15692092416000)*n^14 + (8091120109/747242496000)*n^13 + (255948441937/3621252096000)*n^12 + (100806994639/201180672000)*n^11 + (447955595981/219469824000)*n^10 + (936116756663/73156608000)*n^9 + (89792239149827/2414168064000)*n^8 + (167645449561/1026432000)*n^7 + (5108091310778959/11769069312000)*n^6 - (433115879452601/217945728000)*n^5 + (6324467156344901/653837184000)*n^4 - (35759831917609/698544000)*n^3 + (1815894225096923/15437822400)*n^2 + (1874103131609/6126120)*n - 1349188 for n>9.

Extensions

Name corrected by Andrew Howroyd, Mar 18 2025