A234558 Number of (n+1) X (2+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4 (constant-stress 1 X 1 tilings).

220, 546, 1240, 3384, 8416, 24420, 64240, 194124, 527920, 1640076, 4548400, 14411004, 40441936, 130023180, 367611280, 1195404444, 3396165040, 11145399276, 31767426160, 105049443324, 300084387856, 998758590540, 2857390403920

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +30*a(n-2) -132*a(n-3) -331*a(n-4) +1720*a(n-5) +1530*a(n-6) -11280*a(n-7) -1324*a(n-8) +39136*a(n-9) -12360*a(n-10) -67968*a(n-11) +39456*a(n-12) +46080*a(n-13) -34560*a(n-14)

Example

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

Crossrefs

Column 2 of A234564.

Sequence in context: A175738 A260203 A184543 * A211816 A135807 A258545

Adjacent sequences: A234555 A234556 A234557 * A234559 A234560 A234561

Keyword

nonn

Author

R. H. Hardin, Dec 28 2013

Status

approved