A267729 Number of n X 2 0..1 arrays with every repeated value in every row and column greater than or equal to the previous repeated value.

4, 16, 64, 225, 784, 2601, 8464, 26896, 84100, 259081, 788544, 2374681, 7086244, 20976400, 61653904, 180069561, 522945424, 1510954641, 4345446400, 12444741136, 35502850084, 100926300721, 285976813824, 807886380625, 2275928269924

Offset: 1

Author

R. H. Hardin, Jan 20 2016

Keywords

• nonn

Comments

Column 2 of A267735.

Examples

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

Links

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

Crossrefs

Cf. A267735.

Formula

Empirical: a(n) = 6*a(n-1) - 6*a(n-2) - 19*a(n-3) + 24*a(n-4) + 24*a(n-5) - 19*a(n-6) - 6*a(n-7) + 6*a(n-8) - a(n-9).

Empirical g.f.: x*(4 - 8*x - 8*x^2 + 13*x^3 + 26*x^4 - 17*x^5 - 7*x^6 + 6*x^7 - x^8) / ((1 + x)^3*(1 - 3*x + x^2)^3). - Colin Barker, Mar 21 2018