A280475 Number of nX3 0..2 arrays with no element unequal 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, 22, 208, 1939, 17406, 149057, 1224092, 9717407, 75078490, 567486429, 4212636472, 30802884219, 222362166198, 1587624277241, 11227499711316, 78737492563415, 548110879578258, 3790518591777685, 26059838687117808

Offset

1,2

Comments

Column 3 of A280480.

Links

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

Formula

Empirical: a(n) = 27*a(n-1) -303*a(n-2) +1857*a(n-3) -6924*a(n-4) +16608*a(n-5) -26048*a(n-6) +26112*a(n-7) -15360*a(n-8) +4096*a(n-9) for n>10

Example

Some solutions for n=4
..0..0..1. .0..0..0. .0..0..0. .0..0..1. .0..0..1. .0..1..1. .0..1..1
..1..1..2. .1..2..0. .0..0..1. .0..1..0. .0..1..1. .1..0..0. .1..1..2
..2..2..0. .0..0..2. .0..0..2. .0..0..0. .2..2..1. .0..0..2. .1..2..0
..1..1..1. .0..2..2. .0..0..0. .0..2..2. .0..0..0. .1..1..1. .0..0..0

Crossrefs

Cf. A280480.

Sequence in context: A376946 A274982 A144249 * A010828 A022714 A302924

Adjacent sequences: A280472 A280473 A280474 * A280476 A280477 A280478

Keyword

nonn

Author

R. H. Hardin, Jan 04 2017

Status

approved