A279978 Number of 2 X n 0..1 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

0, 3, 9, 24, 62, 134, 277, 542, 1035, 1930, 3546, 6432, 11555, 20590, 36445, 64140, 112326, 195866, 340241, 589038, 1016671, 1749950, 3004610, 5147092, 8798911, 15012766, 25569393, 43477440, 73814414, 125140142, 211870477, 358260350

Offset: 1

Author

R. H. Hardin, Dec 24 2016

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 2 of A279977.

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>10.

Empirical g.f.: x^2*(3 - 6*x + 11*x^3 - 20*x^4 + 5*x^5 + 12*x^6 + 2*x^7 - 5*x^8) / ((1 - x)^2*(1 - x - x^2)^3). - Colin Barker, Feb 12 2019