A234139 Number of (n+1) X (7+1) 0..3 arrays with every 2 X 2 subblock having the sum of the absolute values of all six edge and diagonal differences equal to 9.

9216, 9992, 11336, 14120, 19368, 30632, 53288, 104744, 214056, 481832, 1079336, 2667560, 6361128, 16893992, 42139688, 117796904, 302637096, 873644072, 2284036136, 6715433000, 17725595688, 52630822952, 139620917288, 416680321064

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 8*a(n-2) - 30*a(n-3) + 4*a(n-4) + 48*a(n-5) - 32*a(n-6).

Empirical g.f.: 8*x*(1152 - 2207*x - 11546*x^2 + 22082*x^3 + 18652*x^4 - 35336*x^5) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 13 2018

Example

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

Crossrefs

Column 7 of A234140.

Sequence in context: A231424 A234887 A251902 * A175743 A204103 A209595

Adjacent sequences: A234136 A234137 A234138 * A234140 A234141 A234142

Keyword

nonn

Author

R. H. Hardin, Dec 19 2013

Status

approved