A223931 Number of nX6 0..2 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.

148, 4690, 49646, 316136, 1548633, 6621074, 26250443, 98910688, 356869229, 1233491661, 4078987936, 12893958739, 38971222534, 112766372283, 313016886779, 835552379045, 2150549167905, 5351315229801, 12907390753903, 30251757926890

Offset: 1

Author

R. H. Hardin Mar 29 2013

Keywords

• nonn

Comments

Column 6 of A223933

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..141

Formula

Empirical: a(n) = (1/35608838483312640000)*n^24 - (1/989134402314240000)*n^23 + (1/12843374100480000)*n^22 - (6449/4257578514309120000)*n^21 + (21257/304112751022080000)*n^20 - (829363/1216451004088320000)*n^19 + (40421209/896332318801920000)*n^18 - (9123221/16598746644480000)*n^17 + (633266813/17575143505920000)*n^16 - (337664083/599152619520000)*n^15 + (2727091523/144850083840000)*n^14 - (437501744297/941525544960000)*n^13 + (331492439551297/26362715258880000)*n^12 - (779880875442583/2929190584320000)*n^11 + (6466629168070943/1351934115840000)*n^10 - (1887207111269150711/26362715258880000)*n^9 + (1852948610513538961/2000741783040000)*n^8 - (82282526794806272279/8002967132160000)*n^7 + (671840992562382243287/6956827637760000)*n^6 - (3984160216854431049887/5375730447360000)*n^5 + (4404199128820894274957/985550582016000)*n^4 - (7353970133174044661/365018734080)*n^3 + (398286504848891623/6290282880)*n^2 - (651587469103938359/5354228880)*n + 102401506 for n>12