A234651 Number of (n+1) X (1+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4 (constant-stress 1 X 1 tilings).

160, 728, 3264, 15008, 67840, 315008, 1434624, 6722048, 30822400, 145614848, 671760384, 3197247488, 14829813760, 71052197888, 331140562944, 1595912880128, 7469054033920, 36183831216128, 169965785186304, 827149902675968

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 44*a(n-2) - 176*a(n-3) - 480*a(n-4) + 1920*a(n-5).

Empirical g.f.: 8*x*(20 + 11*x - 836*x^2 - 240*x^3 + 8640*x^4) / ((1 - 4*x)*(1 - 20*x^2)*(1 - 24*x^2)). - Colin Barker, Oct 15 2018

Example

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

Crossrefs

Column 1 of A234658.

Sequence in context: A233917 A233910 A234658 * A234898 A234891 A305272

Adjacent sequences: A234648 A234649 A234650 * A234652 A234653 A234654

Keyword

nonn

Author

R. H. Hardin, Dec 29 2013

Status

approved