A234484 Number of (n+1) X (2+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).

242, 926, 3540, 13554, 51950, 199340, 765738, 2944686, 11336132, 43687010, 168537102, 650861628, 2516088026, 9736457486, 37714463508, 146231331858, 567534230318, 2204734291532, 8572871807370, 33365331185646, 129974035943396

Offset

1,1

Links

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

Formula

Empirical: a(n) = 10*a(n-1) - 28*a(n-2) + a(n-3) + 54*a(n-4) + 24*a(n-5).

Empirical g.f.: 2*x*(121 - 747*x + 528*x^2 + 1920*x^3 + 768*x^4) / ((1 - 4*x)*(1 - 3*x - 2*x^2)*(1 - 3*x - 3*x^2)). - Colin Barker, Oct 15 2018

Example

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

Crossrefs

Column 2 of A234490.

Sequence in context: A070284 A258894 A258887 * A160551 A258886 A354563

Adjacent sequences: A234481 A234482 A234483 * A234485 A234486 A234487

Keyword

nonn

Author

R. H. Hardin, Dec 26 2013

Status

approved