A235291 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3 (constant-stress 1 X 1 tilings).

40, 108, 272, 744, 1888, 5232, 13376, 37536, 96640, 274368, 710912, 2039424, 5314048, 15382272, 40272896, 117459456, 308746240, 906083328, 2389348352, 7047112704, 18631057408, 55167578112, 146146082816, 434084683776

Offset

1,1

Links

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

Formula

Empirical: a(n) = 14*a(n-2) - 48*a(n-4).

Empirical g.f.: 4*x*(10 + 27*x - 72*x^2 - 192*x^3) / ((1 - 6*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 18 2018

Example

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

Crossrefs

Column 1 of A235301.

Sequence in context: A241024 A123992 A235301 * A235893 A192791 A345970

Adjacent sequences: A235288 A235289 A235290 * A235292 A235293 A235294

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved