A218759 Unmatched value maps: number of n X 2 binary arrays indicating the locations of corresponding elements not equal to any horizontal or vertical neighbor in a random 0..1 n X 2 array.

2, 6, 18, 47, 134, 373, 1035, 2889, 8050, 22420, 62477, 174072, 484983, 1351277, 3764915, 10489750, 29226504, 81430659, 226881448, 632135485, 1761251171, 4907184849, 13672362150, 38093833868, 106136756981, 295717444696

Offset

1,1

Comments

Column 2 of A218765.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + a(n-2) + 3*a(n-3) + 2*a(n-5) + 2*a(n-6) - 2*a(n-7).

Empirical g.f.: x*(2 + 2*x + 4*x^2 - x^3 + 4*x^4 - 2*x^6) / (1 - 2*x - x^2 - 3*x^3 - 2*x^5 - 2*x^6 + 2*x^7). - Colin Barker, Mar 10 2018

Example

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

Crossrefs

Cf. A218765.

Sequence in context: A002529 A217526 A018027 * A295499 A059413 A256828

Adjacent sequences: A218756 A218757 A218758 * A218760 A218761 A218762

Keyword

nonn

Author

R. H. Hardin, Nov 05 2012

Status

approved