A235303 Number of (n+1) X (1+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 6 (constant-stress 1 X 1 tilings).

70, 210, 518, 1554, 4006, 12018, 32006, 96018, 261670, 785010, 2173958, 6521874, 18267046, 54801138, 154764806, 464294418, 1319524390, 3958573170, 11307598598, 33922795794, 97317170086, 291951510258, 840713542406, 2522140627218

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 13*a(n-2) - 39*a(n-3) - 40*a(n-4) + 120*a(n-5).

Empirical g.f.: 2*x*(35 - 511*x^2 + 1800*x^4) / ((1 - 3*x)*(1 - 5*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 18 2018

Example

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

Crossrefs

Column 1 of A235310.

Sequence in context: A165764 A153669 A235310 * A234564 A234557 A245857

Adjacent sequences: A235300 A235301 A235302 * A235304 A235305 A235306

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved