A279651 Number of n X 2 0..2 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.

1, 3, 24, 232, 2232, 20880, 190656, 1707264, 15046272, 130854656, 1125285888, 9583835136, 80941029376, 678574706688, 5651894845440, 46802046418944, 385539453517824, 3161014415327232, 25806384396763136, 209862489033670656

Offset

1,2

Links

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

Formula

Empirical: a(n) = 24*a(n-1) - 204*a(n-2) + 704*a(n-3) - 816*a(n-4) + 384*a(n-5) - 64*a(n-6) for n>7.

Empirical g.f.: x*(1 - 21*x + 156*x^2 - 436*x^3 + 264*x^4 - 192*x^5 + 32*x^6) / (1 - 8*x + 4*x^2)^3. - Colin Barker, Feb 11 2019

Example

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

Crossrefs

Column 2 of A279657.

Sequence in context: A307514 A225107 A249926 * A001099 A277462 A371522

Adjacent sequences: A279648 A279649 A279650 * A279652 A279653 A279654

Keyword

nonn

Author

R. H. Hardin, Dec 16 2016

Status

approved