A201500 Number of n X 3 0..1 arrays with every row and column running average nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.

2, 2, 6, 5, 12, 8, 20, 13, 30, 18, 42, 25, 56, 32, 72, 41, 90, 50, 110, 61, 132, 72, 156, 85, 182, 98, 210, 113, 240, 128, 272, 145, 306, 162, 342, 181, 380, 200, 420, 221, 462, 242, 506, 265, 552, 288, 600, 313, 650, 338, 702, 365, 756, 392, 812, 421, 870, 450, 930, 481

Offset: 1

Author

R. H. Hardin, Dec 02 2011

Keywords

• nonn

Comments

Column 3 of A201503.

Examples

			All solutions for n=4:
..0..0..1....0..0..0....0..0..0....0..0..0....0..0..1
..0..0..1....0..0..1....0..1..1....0..0..0....0..0..1
..0..0..1....0..1..1....0..1..1....1..1..1....0..1..1
..1..1..1....1..1..1....0..1..1....1..1..1....0..1..1
		

Links

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

Crossrefs

Cf. A201503.

Formula

Empirical: a(n) = 2*a(n-2) -2*a(n-6) +a(n-8).

Odd terms are A002378((n+1)/2).

Even terms are A000982((n+2)/2).

Empirical g.f.: x*(2 + 2*x + 2*x^2 + x^3 - 2*x^5 + x^7) / ((1 - x)^3*(1 + x)^3*(1 + x^2)). - Colin Barker, May 23 2018