A234154 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the absolute values of all six edge and diagonal differences no larger than 1.

46, 226, 1108, 5446, 26794, 131896, 649450, 3198322, 15751828, 77581198, 382112002, 1882042264, 9269800642, 45657552106, 224882405380, 1107640064854, 5455593492922, 26871099434488, 132351514215994, 651887143644034

Offset

1,1

Links

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

Formula

Empirical: a(n) = 7*a(n-1) - 9*a(n-2) - 6*a(n-3).

Empirical g.f.: 2*x*(23 - 48*x - 30*x^2) / (1 - 7*x + 9*x^2 + 6*x^3). - Colin Barker, Oct 13 2018

Example

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

Crossrefs

Column 1 of A234161.

Sequence in context: A083358 A254229 A234161 * A251410 A251403 A026913

Adjacent sequences: A234151 A234152 A234153 * A234155 A234156 A234157

Keyword

nonn

Author

R. H. Hardin, Dec 20 2013

Status

approved