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

1,1

Comments

Column 2 of A267735.

Links

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

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

Example

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

Crossrefs

Cf. A267735.

Sequence in context: A177398 A343200 A227312 * A189154 A189336 A262334

Adjacent sequences: A267726 A267727 A267728 * A267730 A267731 A267732

Keyword

nonn

Author

R. H. Hardin, Jan 20 2016

Status

approved