A234264 Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).

1336, 1690, 2324, 3616, 6076, 11140, 21164, 42076, 84556, 174700, 361484, 766156, 1619596, 3513100, 7574924, 16818316, 36974476, 84005260, 188124044, 436672396, 994194316, 2351102860, 5427635084, 13031887756, 30417011596, 73894388620

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 6*a(n-2) - 24*a(n-3) + 4*a(n-4) + 36*a(n-5) - 24*a(n-6).

Empirical g.f.: 2*x*(668 - 1159*x - 5381*x^2 + 9284*x^3 + 8250*x^4 - 13932*x^5) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 6*x^2)). - Colin Barker, Oct 14 2018

Example

Some solutions for n=5:
  2 0 0 0 2 2 2       0 0 0 2 0 0 0       1 1 1 1 2 0 1
  2 2 0 2 2 0 2       0 2 0 0 0 2 0       0 2 0 2 1 1 0
  2 0 0 0 2 2 2       2 2 2 0 2 2 2       1 1 1 1 2 0 1
  2 2 0 2 2 0 2       0 2 0 0 0 2 0       0 2 0 2 1 1 0
  2 0 0 0 2 2 2       2 2 2 0 2 2 2       1 1 1 1 2 0 1
  0 0 2 0 0 2 0       0 2 0 0 0 2 0       0 2 0 2 1 1 0

Crossrefs

Column 6 of A234266.

Sequence in context: A250902 A250946 A145494 * A237476 A206049 A239254

Adjacent sequences: A234261 A234262 A234263 * A234265 A234266 A234267

Keyword

nonn

Author

R. H. Hardin, Dec 22 2013

Status

approved