A234265 Number of (n+1) X (7+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).

3104, 3746, 4924, 7304, 11876, 21164, 39508, 77060, 152564, 308756, 627124, 1294964, 2673716, 5617844, 11778868, 25220660, 53769524, 117585716, 255267124, 570940724, 1262696756, 2888073524, 6501509428, 15179569460, 34712242484

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*(1552 - 2783*x - 12469*x^2 + 22276*x^3 + 18954*x^4 - 33420*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:
  0 2 2 0 0 2 0 2     2 2 0 0 0 2 0 0     0 0 2 0 0 2 2 2
  0 0 2 2 0 0 0 0     2 0 0 2 0 0 0 2     2 0 0 0 2 2 0 2
  2 0 0 2 2 0 2 0     0 0 2 2 2 0 2 2     0 0 2 0 0 2 2 2
  2 2 0 0 2 2 2 2     2 0 0 2 0 0 0 2     2 0 0 0 2 2 0 2
  0 2 2 0 0 2 0 2     2 2 0 0 0 2 0 0     2 2 0 2 2 0 0 0
  2 2 0 0 2 2 2 2     0 2 2 0 2 2 2 0     2 0 0 0 2 2 0 2

Crossrefs

Column 7 of A234266.

Sequence in context: A252884 A103523 A345519 * A090056 A229410 A257356

Adjacent sequences: A234262 A234263 A234264 * A234266 A234267 A234268

Keyword

nonn

Author

R. H. Hardin, Dec 22 2013

Status

approved