A235205 Number of (n+1) X (1+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 5, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

240, 1172, 5696, 27812, 135520, 662892, 3236288, 15860868, 77573344, 380902284, 1866159680, 9179924964, 45049615456, 221990217900, 1091105210048, 5385447685188, 26509233788896, 131045666620620, 645952788233024

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 35*a(n-2) - 81*a(n-3) - 264*a(n-4) + 144*a(n-5) + 384*a(n-6).

Empirical g.f.: 4*x*(60 + 113*x - 1555*x^2 - 2714*x^3 + 2754*x^4 + 4784*x^5) / ((1 - 3*x - 8*x^2)*(1 - 27*x^2 + 48*x^4)). - Colin Barker, Oct 17 2018

Example

Some solutions for n=5:
  3 0   3 0   3 4   4 1   2 6   1 2   1 2   6 2   0 4   7 0
  1 3   5 7   6 2   1 3   3 2   4 0   7 3   4 5   3 2   4 2
  4 1   7 4   2 3   5 2   1 5   6 7   5 6   1 7   2 6   2 5
  2 4   3 5   4 0   3 5   7 6   7 3   6 2   3 4   4 3   6 4
  4 1   0 7   0 1   7 4   6 0   1 2   5 6   4 0   0 4   7 0
  5 7   4 6   7 3   0 2   4 3   7 3   6 2   6 7   4 3   4 2

Crossrefs

Column 1 of A235212.

Sequence in context: A234728 A234721 A235212 * A233878 A157766 A268906

Adjacent sequences: A235202 A235203 A235204 * A235206 A235207 A235208

Keyword

nonn

Author

R. H. Hardin, Jan 04 2014

Status

approved