A234667 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 4 (constant-stress 1 X 1 tilings).

492, 3816, 29568, 229272, 1778412, 13801056, 107144508, 832197192, 6466444032, 50269824456, 390963554148, 3042084148512, 23680823914452, 184429911964056, 1437009243823488, 11202089753841432, 87364420495436172, 681684020356757856

Offset

1,1

Links

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

Formula

Empirical: a(n) = 14*a(n-1) + 25*a(n-2) - 950*a(n-3) + 2091*a(n-4) + 7326*a(n-5) - 3780*a(n-6) - 10080*a(n-7).

Empirical g.f.: 12*x*(41 - 256*x - 3013*x^2 + 15610*x^3 + 35486*x^4 - 26880*x^5 - 53760*x^6) / ((1 - 8*x)*(1 - 6*x - 12*x^2)*(1 - 61*x^2 + 105*x^4)). - Colin Barker, Oct 16 2018

Example

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

Crossrefs

Column 1 of A234672.

Sequence in context: A226715 A205819 A234672 * A231455 A007242 A198531

Adjacent sequences: A234664 A234665 A234666 * A234668 A234669 A234670

Keyword

nonn

Author

R. H. Hardin, Dec 29 2013

Status

approved