A223775 Number of n X 6 0..1 arrays with rows and columns unimodal and antidiagonals nondecreasing.

22, 169, 707, 2164, 5573, 12975, 28346, 59231, 119555, 234348, 447489, 834107, 1520016, 2711565, 4740623, 8131175, 13696273, 22676975, 36938539, 59243658, 93628083, 145910759, 224378788, 340697347, 511106363, 757979538, 1111837505

Offset: 1

Author

R. H. Hardin Mar 27 2013

Keywords

• nonn

Comments

Column 6 of A223777.

Examples

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

Links

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

Crossrefs

Cf. A223777.

Formula

Empirical: a(n) = (1/479001600)*n^12 + (1/26611200)*n^11 + (11/8709120)*n^10 + (1/53760)*n^9 + (6271/14515200)*n^8 + (493/115200)*n^7 + (320657/8709120)*n^6 + (157151/483840)*n^5 + (41441549/10886400)*n^4 - (451279/67200)*n^3 + (49282619/332640)*n^2 - (20927/44)*n + 563 for n>3.