A235100 Number of (n+1) X (1+1) 0..6 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 4, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

154, 670, 2900, 12578, 54530, 236496, 1025770, 4449942, 19307284, 83782730, 363623322, 1578383808, 6852296402, 29752369022, 129201632884, 561144450002, 2437478108882, 10589252938544, 46009511768922, 199934061184966

Offset

1,1

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 2*a(n-2) - 47*a(n-3) + 3*a(n-4) + 84*a(n-5) + 36*a(n-6).

Empirical g.f.: 2*x*(77 - 204*x - 741*x^2 + 428*x^3 + 1656*x^4 + 648*x^5) / ((1 - 3*x - 6*x^2)*(1 - 4*x - 4*x^2 + 11*x^3 + 6*x^4)). - Colin Barker, Oct 17 2018

Example

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

Crossrefs

Column 1 of A235107.

Sequence in context: A239564 A250626 A235107 * A230804 A200552 A160854

Adjacent sequences: A235097 A235098 A235099 * A235101 A235102 A235103

Keyword

nonn

Author

R. H. Hardin, Jan 03 2014

Status

approved