A224199 Number of nX3 0..3 arrays with rows unimodal and antidiagonals nondecreasing.

50, 984, 16060, 263516, 4357084, 72105068, 1193130640, 19742052632, 326659600368, 5405039750704, 89433956076272, 1479810123371280, 24485531969701600, 405147434704078656, 6703731985610244736

Offset: 1

Author

R. H. Hardin Apr 01 2013

Keywords

• nonn

Comments

Column 3 of A224204

Examples

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

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -70*a(n-2) +228*a(n-3) -276*a(n-4) +392*a(n-5) -196*a(n-6) +144*a(n-7)