A224191 Number of 4Xn 0..2 arrays with rows unimodal and columns nondecreasing.

15, 225, 2205, 15779, 89380, 422488, 1727738, 6272940, 20614382, 62231446, 174603882, 459586532, 1143581612, 2707062766, 6128575771, 13328965295, 27955737041, 56730240471, 111704250407, 213954477597, 399506181220

Offset: 1

Author

R. H. Hardin Apr 01 2013

Keywords

• nonn

Comments

Row 4 of A224190

Examples

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

Links

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

Formula

Empirical: a(n) = (1/106748928000)*n^16 + (1/1482624000)*n^15 + (7/266872320)*n^14 + (127/197683200)*n^13 + (311999/28740096000)*n^12 + (212351/1596672000)*n^11 + (31937/26127360)*n^10 + (83129/9676800)*n^9 + (34840531/746496000)*n^8 + (9481183/48384000)*n^7 + (90994151/143700480)*n^6 + (123257231/79833600)*n^5 + (43399375531/15567552000)*n^4 + (2360326763/648648000)*n^3 + (218135/61776)*n^2 + (581099/360360)*n + 1