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

1,1

Comments

Column 6 of A223777.

Links

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

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.

Example

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

Crossrefs

Cf. A223777.

Sequence in context: A067561 A223768 A224156 * A224407 A243143 A321268

Adjacent sequences: A223772 A223773 A223774 * A223776 A223777 A223778

Keyword

nonn

Author

R. H. Hardin Mar 27 2013

Status

approved