A224264 Number of 4 X n 0..2 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.

15, 225, 2017, 12467, 59855, 240829, 850875, 2717731, 8000608, 22004896, 57114321, 140968221, 332855049, 755508149, 1654943378, 3509994992, 7227765020, 14484196632, 28304567857, 54032736159, 100918573991, 184671328897, 331497593861, 584386115169, 1012744010692

Offset: 1

Author

R. H. Hardin, Apr 02 2013

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 4 of A224262.

Formula

Empirical: a(n) = (1/106748928000)*n^16 + (1/13343616000)*n^15 + (71/9340531200)*n^14 + (341/3396556800)*n^13 + (70619/28740096000)*n^12 + (6403/186624000)*n^11 + (29921/65318400)*n^10 + (938611/261273600)*n^9 + (179393437/5225472000)*n^8 + (211646789/1306368000)*n^7 + (955811279/1437004800)*n^6 + (152465767/51321600)*n^5 - (11075280679/15567552000)*n^4 - (274011991/117936000)*n^3 + (8155853/123552)*n^2 - (184217/936)*n + 242 for n>2.

Extensions

Name corrected by Andrew Howroyd, Mar 18 2025