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

1,3

Comments

Column 2 of A279134.

Links

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

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

Example

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

Crossrefs

Cf. A279134.

Sequence in context: A133547 A100179 A106598 * A293038 A326278 A014816

Adjacent sequences: A279125 A279126 A279127 * A279129 A279130 A279131

Keyword

nonn

Author

R. H. Hardin, Dec 06 2016

Status

approved