A279128 Number of n X 2 0..1 arrays with no element equal to a strict majority of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

1, 0, 9, 34, 87, 194, 400, 790, 1511, 2830, 5213, 9484, 17080, 30508, 54117, 95434, 167443, 292486, 508912, 882402, 1525219, 2628886, 4519577, 7751888, 13267384, 22662360, 38639553, 65769394, 111771663, 189671306, 321421456, 543987118

Offset: 1

Author

R. H. Hardin, Dec 06 2016

Keywords

• nonn

Comments

Column 2 of A279134.

Examples

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

Links

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

Crossrefs

Cf. A279134.

Formula

Empirical: a(n) = 5*a(n-1) - 7*a(n-2) - 2*a(n-3) + 10*a(n-4) - 2*a(n-5) - 5*a(n-6) + a(n-7) + a(n-8) for n>9.

Empirical g.f.: x*(1 - 5*x + 16*x^2 - 9*x^3 - 30*x^4 + 17*x^5 + 22*x^6 - x^7 - 9*x^8) / ((1 - x)^2*(1 - x - x^2)^3). - Colin Barker, Feb 26 2018