A234437 Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 1 (constant-stress 1 X 1 tilings).

120, 582, 2804, 13676, 66228, 324556, 1578036, 7767916, 37908724, 187373548, 917502516, 4551845676, 22356377716, 111280430060, 548022172852, 2735782774700, 13504607285492, 67587887187308, 334314078617908

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 24*a(n-2) - 130*a(n-3) + 36*a(n-4) + 80*a(n-5) - 32*a(n-6).

Empirical g.f.: 2*x*(60 - 9*x - 1493*x^2 + 644*x^3 + 946*x^4 - 420*x^5) / ((1 - 5*x + 2*x^2)*(1 - 26*x^2 + 16*x^4)). - Colin Barker, Oct 15 2018

Example

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

Crossrefs

Column 2 of A234443.

Sequence in context: A115619 A152622 A100145 * A090216 A265041 A280425

Adjacent sequences: A234434 A234435 A234436 * A234438 A234439 A234440

Keyword

nonn

Author

R. H. Hardin, Dec 26 2013

Status

approved