A223865 Number of 2Xn 0..3 arrays with rows and antidiagonals unimodal and columns nondecreasing.

10, 100, 684, 3526, 14751, 52591, 165212, 468292, 1218812, 2951732, 6721028, 14507390, 29883426, 59065484, 112531519, 207449471, 371243434, 646728936, 1099377792, 1827431562, 2975775445, 4754716769, 7465089922, 11531438986

Offset: 1

Author

R. H. Hardin Mar 28 2013

Keywords

• nonn

Comments

Row 2 of A223864

Examples

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

Links

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

Formula

Empirical: a(n) = (1/19160064)*n^12 + (1/456192)*n^11 + (2287/43545600)*n^10 + (215/290304)*n^9 + (3991/580608)*n^8 + (2369/53760)*n^7 + (8836141/43545600)*n^6 + (136571/207360)*n^5 + (654599/435456)*n^4 + (865283/362880)*n^3 + (289699/103950)*n^2 + (39143/27720)*n + 1