A234162 Number of (n+1) X (1+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2 (constant-stress 1 X 1 tilings).

136, 766, 4296, 24158, 135752, 764190, 4299592, 24233182, 136504392, 770285726, 4343950664, 24541377630, 138552612424, 783650013214, 4428992339784, 25077751366622, 141879999973448, 804197213585310, 4554351695155528

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 41*a(n-2) - 132*a(n-3) - 264*a(n-4).

Empirical g.f.: 2*x*(68 + 111*x - 2172*x^2 - 3240*x^3) / ((1 - 4*x - 8*x^2)*(1 - 33*x^2)). - Colin Barker, Oct 13 2018

Example

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

Crossrefs

Column 1 of A234169.

Sequence in context: A183901 A270341 A234169 * A262091 A251175 A251168

Adjacent sequences: A234159 A234160 A234161 * A234163 A234164 A234165

Keyword

nonn

Author

R. H. Hardin, Dec 20 2013

Status

approved