A235274 Number of (n+1) X (4+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).

520, 844, 1280, 2344, 3952, 7936, 14672, 31504, 62800, 141424, 298640, 695344, 1530832, 3647536, 8265872, 20008624, 46236880, 113126704, 264832400, 652640944, 1540956112, 3815788336, 9060105872, 22507117744, 53636823760, 133528827184

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*(130 + 81*x - 1841*x^2 - 949*x^3 + 9167*x^4 + 3486*x^5 - 19026*x^6 - 4032*x^7 + 13824*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 18 2018

Example

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

Crossrefs

Column 4 of A235280.

Sequence in context: A043626 A345596 A345855 * A147854 A147856 A094903

Adjacent sequences: A235271 A235272 A235273 * A235275 A235276 A235277

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved