A252945 Number of (n+2) X (1+2) 0..2 arrays with every consecutive three elements in every row, column and nw-se diagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.

198, 747, 2970, 11943, 48024, 193059, 776160, 3120579, 12546540, 50444415, 202816008, 815438907, 3278541276, 13181653431, 52997956416, 213082782147, 856717412004, 3444505073199, 13848925017096, 55680778531323

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 9*a(n-2) + 4*a(n-3) + 2*a(n-4) - 6*a(n-5) + 4*a(n-6).

Empirical g.f.: 9*x*(22 - 49*x + 30*x^2 + 6*x^3 - 32*x^4 + 24*x^5) / ((1 - x)*(1 - 5*x + 4*x^2 - 2*x^4 + 4*x^5)). - Colin Barker, Dec 07 2018

Example

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

Crossrefs

Column 1 of A252952.

Sequence in context: A304614 A357076 A252952 * A158222 A156771 A065697

Adjacent sequences: A252942 A252943 A252944 * A252946 A252947 A252948

Keyword

nonn

Author

R. H. Hardin, Dec 25 2014

Status

approved