A185469 Number of (n+2)X3 0..2 arrays with each 3X3 subblock having rows and columns in lexicographically nondecreasing order.

1169, 4594, 13659, 34779, 79743, 169052, 336690, 636698, 1151966, 2005704, 3376100, 5514721, 8769262, 13611298, 20669745, 30770788, 44985087, 64683126, 91599625, 127907991, 176305841, 240112688, 323380940, 431021422, 568944692

Offset: 1

Author

R. H. Hardin Jan 28 2011

Keywords

• nonn

Comments

Column 1 of A185477

Examples

			Some solutions for 4X3
..1..1..2....0..1..2....0..0..0....0..1..2....0..0..1....0..0..0....0..0..2
..1..1..2....0..1..2....0..0..2....0..1..2....0..1..1....0..0..2....0..2..2
..1..2..1....0..1..2....0..2..1....1..1..0....0..2..2....0..1..0....1..0..1
..2..0..1....2..1..2....2..0..0....2..0..1....1..0..1....0..2..0....2..0..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = (1/362880)*n^9

+ (1/1008)*n^8

+ (431/12096)*n^7

+ (373/720)*n^6

+ (82453/17280)*n^5

+ (637/18)*n^4

+ (2819461/18144)*n^3

+ (119729/315)*n^2

+ (605807/1260)*n

+ 112