A252963 Number of (2+2) X (n+2) 0..4 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.

140, 120, 155, 249, 385, 651, 1069, 1757, 2949, 5045, 8293, 14403, 24247, 41597, 70611, 122969, 207079, 362631, 615901, 1073777, 1829085, 3205565, 5445181, 9561243, 16288711, 28558037, 48700563, 85534529, 145725655, 256108431

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 3*a(n-2) + 2*a(n-3) - 5*a(n-4) - 15*a(n-5) + 9*a(n-6) + 6*a(n-7) + 18*a(n-8) - 18*a(n-9) for n>12.

Empirical g.f.: x*(140 - 20*x - 385*x^2 - 546*x^3 + 131*x^4 + 1909*x^5 + 80*x^6 - 385*x^7 - 2292*x^8 + 906*x^9 + 408*x^10 + 36*x^11) / ((1 - x)*(1 - 3*x^2)*(1 - 2*x^3)*(1 - 3*x^3)). - Colin Barker, Dec 07 2018

Example

Some solutions for n=2:
..0..0..1..0....0..1..0..0....0..1..0..0....0..0..1..0....0..0..1..1
..0..2..2..0....2..2..1..1....1..2..1..1....2..0..0..1....2..2..3..3
..0..3..0..0....3..3..2..2....3..3..2..2....3..0..3..3....4..4..0..0
..0..0..3..0....0..0..3..3....0..0..3..3....0..0..2..0....1..1..2..2

Crossrefs

Row 2 of A252961.

Sequence in context: A183491 A215571 A108317 * A114825 A308617 A353074

Adjacent sequences: A252960 A252961 A252962 * A252964 A252965 A252966

Keyword

nonn

Author

R. H. Hardin, Dec 25 2014

Status

approved