A234705 Number of (n+1) X (1+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).

322, 1730, 8738, 47306, 239890, 1308890, 6664130, 36647114, 187332082, 1038190010, 5327738018, 29749954346, 153244107730, 861925872410, 4455708286850, 25233168686474, 130879192683442, 745921619501690

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 84*a(n-2) - 420*a(n-3) - 2336*a(n-4) + 11680*a(n-5) + 21504*a(n-6) - 107520*a(n-7).

Empirical g.f.: 2*x*(161 + 60*x - 13480*x^2 - 3232*x^3 + 374080*x^4 + 43008*x^5 - 3440640*x^6) / ((1 - 5*x)*(1 - 24*x^2)*(1 - 28*x^2)*(1 - 32*x^2)). - Colin Barker, Oct 16 2018

Example

Some solutions for n=4:
  5 5   2 2   0 0   2 0   0 2   0 6   0 6   7 7   2 3   6 7
  0 6   1 7   1 7   1 5   4 0   3 3   1 1   0 6   0 7   0 7
  6 6   0 0   0 0   4 2   0 2   1 7   6 0   2 2   0 1   1 2
  6 0   6 0   7 1   3 7   4 0   3 3   2 2   7 1   6 1   0 7
  2 2   4 4   3 3   2 0   3 5   0 6   0 6   7 7   0 1   3 4

Crossrefs

Column 1 of A234712.

Sequence in context: A158305 A237406 A234712 * A324629 A234704 A266885

Adjacent sequences: A234702 A234703 A234704 * A234706 A234707 A234708

Keyword

nonn

Author

R. H. Hardin, Dec 29 2013

Status

approved