A223956 Number of nX3 0..3 arrays with antidiagonals unimodal and rows and diagonals nondecreasing.

20, 295, 3471, 41006, 485714, 5777663, 68892600, 822141033, 9813968785, 117159879996, 1398692077165, 16698106010927, 199348287106117, 2379894628461976, 28412070357384947, 339193873130519142

Offset: 1

Author

R. H. Hardin Mar 29 2013

Keywords

• nonn

Comments

Column 3 of A223961

Examples

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

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -105*a(n-2) +51*a(n-3) +589*a(n-4) +1340*a(n-5) -8833*a(n-6) -2855*a(n-7) +30423*a(n-8) +57774*a(n-9) -140760*a(n-10) -176184*a(n-11) +106272*a(n-12) +544320*a(n-13)