A235272 Number of (n+1) X (2+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 5 (constant-stress 1 X 1 tilings).

100, 208, 380, 844, 1660, 3844, 8012, 19060, 41500, 100468, 225740, 552724, 1269340, 3130804, 7297292, 18083860, 42569500, 105816628, 250733900, 624493204, 1486176220, 3706326964, 8845631372, 22078365460, 52792467100, 131840507188

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 15*a(n-2) - 15*a(n-3) - 80*a(n-4) + 80*a(n-5) + 180*a(n-6) - 180*a(n-7) - 144*a(n-8) + 144*a(n-9).

Empirical g.f.: 4*x*(25 + 27*x - 332*x^2 - 289*x^3 + 1559*x^4 + 966*x^5 - 3078*x^6 - 1008*x^7 + 2160*x^8) / ((1 - x)*(1 - 2*x)*(1 + 2*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Oct 17 2018

Example

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

Crossrefs

Column 2 of A235280.

Sequence in context: A053402 A181568 A308306 * A249702 A188245 A122467

Adjacent sequences: A235269 A235270 A235271 * A235273 A235274 A235275

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved