A235016 Number of (n+1) X (7+1) 0..4 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

11400, 14600, 19560, 28968, 44680, 74888, 128776, 235240, 437928, 853928, 1698888, 3513672, 7432648, 16248488, 36317416, 83329384, 194803464, 464181896, 1121480328, 2744583528, 6780016936, 16886392616, 42310371784, 106547257288

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..209

Formula

Empirical: a(n) = 5*a(n-1) + a(n-2) - 38*a(n-3) + 33*a(n-4) + 97*a(n-5) - 127*a(n-6) - 88*a(n-7) + 154*a(n-8) + 12*a(n-9) - 48*a(n-10).

Empirical g.f.: 8*x*(1425 - 5300*x - 8105*x^2 + 43721*x^3 + 7360*x^4 - 127725*x^5 + 24570*x^6 + 152306*x^7 - 36540*x^8 - 58464*x^9) / ((1 - x)*(1 - 2*x)*(1 - x - x^2)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - x - 4*x^2)). - Colin Barker, Oct 17 2018

Example

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

Crossrefs

Column 7 of A235017.

Sequence in context: A237796 A236983 A268841 * A185768 A082440 A083975

Adjacent sequences: A235013 A235014 A235015 * A235017 A235018 A235019

Keyword

nonn

Author

R. H. Hardin, Jan 02 2014

Status

approved