A235292 Number of (n+1) X (2+1) 0..3 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3 (constant-stress 1 X 1 tilings).

108, 232, 476, 1132, 2556, 6532, 15692, 42100, 104988, 290932, 741836, 2101012, 5430876, 15615412, 40720652, 118353940, 310480668, 909550132, 2396120396, 7060652692, 18657656796, 55220768692, 146251030412, 434294562580

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 17*a(n-2) - 57*a(n-3) - 86*a(n-4) + 372*a(n-5) + 76*a(n-6) - 972*a(n-7) + 360*a(n-8) + 864*a(n-9) - 576*a(n-10).

Empirical g.f.: 4*x*(27 - 23*x - 514*x^2 + 479*x^3 + 3395*x^4 - 3368*x^5 - 9102*x^6 + 9324*x^7 + 8352*x^8 - 8640*x^9) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)*(1 - 8*x^2)). - Colin Barker, Oct 18 2018

Example

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

Crossrefs

Column 2 of A235301.

Sequence in context: A095050 A339983 A275996 * A202202 A202195 A242867

Adjacent sequences: A235289 A235290 A235291 * A235293 A235294 A235295

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved