A201697 Number of nX5 0..2 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards.

3, 37, 989, 35390, 930564, 14268351, 142436489, 1034563890, 5898023820, 27803725006, 112491133042, 401503571755, 1290797861479, 3798580774670, 10363168825912, 26478119492263, 63883865534377, 146539437113683

Offset: 1

Author

R. H. Hardin Dec 03 2011

Keywords

• nonn

Comments

Column 5 of A201700

Examples

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

Links

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

Formula

Empirical: a(n) = (39619/523069747200)*n^16 + (4468181/653837184000)*n^15 + (29013757/130767436800)*n^14 + (1283689/849139200)*n^13 - (51508993/2874009600)*n^12 - (43603801/256608000)*n^11 + (2874162577/914457600)*n^10 - (7499289487/457228800)*n^9 + (16169769137/731566080)*n^8 + (30409918103/653184000)*n^7 + (408990763441/718502400)*n^6 - (175356370649/25660800)*n^5 + (317152595889599/10897286400)*n^4 - (27799492117129/412776000)*n^3 + (2720484273811/30270240)*n^2 - (23317530409/360360)*n + 19289