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

1,2

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>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

Example

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

Crossrefs

Row 2 of A279977.

Sequence in context: A079282 A117585 A317474 * A269601 A006684 A342795

Adjacent sequences: A279975 A279976 A279977 * A279979 A279980 A279981

Keyword

nonn

Author

R. H. Hardin, Dec 24 2016

Status

approved