A234138 Number of (n+1) X (6+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.

3584, 4040, 4808, 6440, 9512, 16424, 30632, 65192, 141224, 342440, 807848, 2131880, 5299112, 14779304, 37923752, 109378472, 285821864, 840035240, 2216856488, 6581111720, 17457023912, 52093750184, 138546908072, 414532438952

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*(448 - 839*x - 4498*x^2 + 8402*x^3 + 7324*x^4 - 13448*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 0 3 0 3       0 0 1 3 3 0 3       3 3 0 0 3 3 3
  0 0 3 3 3 3 3       0 3 1 0 3 3 3       0 3 3 0 0 3 0
  3 0 0 3 0 3 0       0 0 1 3 3 0 3       3 3 0 0 3 3 3
  0 0 3 3 3 3 3       0 3 1 0 3 3 3       3 0 0 3 3 0 3
  3 0 0 3 0 3 0       0 0 1 3 3 0 3       3 3 0 0 3 3 3
  3 3 0 0 0 0 0       0 3 1 0 3 3 3       0 3 3 0 0 3 0

Crossrefs

Column 6 of A234140.

Sequence in context: A004972 A246855 A252153 * A249289 A249537 A156845

Adjacent sequences: A234135 A234136 A234137 * A234139 A234140 A234141

Keyword

nonn

Author

R. H. Hardin, Dec 19 2013

Status

approved