A223916 Number of nX6 0..2 arrays with rows and antidiagonals unimodal and columns nondecreasing

148, 4102, 45988, 323394, 1721356, 7526024, 28247478, 93683295, 280338123, 769012348, 1958026231, 4673735444, 10543684618, 22631328296, 46477583300, 91756934105, 174838318505, 322648096420, 578369211133, 1009683032422

Offset

1,1

Comments

Column 6 of A223918

Links

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

Formula

Empirical: a(n) = (761/8553600)*n^12 + (761/475200)*n^11 + (21583/1088640)*n^10 + (458/2835)*n^9 + (1760837/1814400)*n^8 + (1346021/302400)*n^7 + (430403/31104)*n^6 + (19199/480)*n^5 + (88406683/1360800)*n^4 + (13099679/226800)*n^3 - (3421811/41580)*n^2 - (5265011/13860)*n + 389 for n>3

Example

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

Crossrefs

Sequence in context: A121280 A338970 A224260 * A224188 A223931 A224055

Adjacent sequences: A223913 A223914 A223915 * A223917 A223918 A223919

Keyword

nonn

Author

R. H. Hardin Mar 29 2013

Status

approved