A234697 Number of (n+1) X (1+1) 0..7 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 5 (constant-stress 1 X 1 tilings).

408, 2628, 16848, 109224, 704160, 4594320, 29782080, 195532704, 1274237568, 8416415808, 55124437248, 366185867904, 2409750673920, 16093719394560, 106373608473600, 713965515692544, 4738136283260928, 31947371388453888

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 90*a(n-2) - 540*a(n-3) - 2016*a(n-4) + 12096*a(n-5).

Empirical g.f.: 12*x*(34 + 15*x - 2970*x^2 - 672*x^3 + 64512*x^4) / ((1 - 6*x)*(1 - 42*x^2)*(1 - 48*x^2)). - Colin Barker, Oct 16 2018

Example

Some solutions for n=4:
  7 7   7 2   7 2   5 4   5 2   1 7   4 0   2 5   4 3   6 0
  0 5   0 0   7 7   3 7   0 2   0 1   6 7   5 3   0 4   1 0
  7 7   6 1   2 7   7 6   6 3   4 0   0 6   1 4   1 0   2 6
  5 0   5 5   0 0   3 7   1 3   0 1   5 6   6 4   3 7   6 5
  7 7   1 6   6 1   5 4   7 4   5 1   4 0   0 3   7 6   0 4

Crossrefs

Column 1 of A234702.

Sequence in context: A067674 A157263 A234702 * A337795 A183717 A285767

Adjacent sequences: A234694 A234695 A234696 * A234698 A234699 A234700

Keyword

nonn

Author

R. H. Hardin, Dec 29 2013

Status

approved