A234984 Number of (n+1) X (1+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 2, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings).

90, 370, 1640, 7554, 35072, 163416, 762002, 3554334, 16580250, 77345792, 360815494, 1683196556, 7852080772, 36629820538, 170877487282, 797140579074, 3718647299872, 17347426713674, 80925452066672, 377515864606272

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 6*a(n-2) - 33*a(n-3) - 24*a(n-4) + 56*a(n-5) + 34*a(n-6) - 20*a(n-7) - 4*a(n-8).

Empirical g.f.: 2*x*(45 - 40*x - 375*x^2 + 52*x^3 + 916*x^4 + 346*x^5 - 324*x^6 - 60*x^7) / ((1 - 2*x^2)*(1 - 5*x - 4*x^2 + 23*x^3 + 16*x^4 - 10*x^5 - 2*x^6)). - Colin Barker, Oct 16 2018

Example

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

Crossrefs

Column 1 of A234991.

Sequence in context: A157888 A201103 A234991 * A158490 A304618 A187300

Adjacent sequences: A234981 A234982 A234983 * A234985 A234986 A234987

Keyword

nonn

Author

R. H. Hardin, Jan 02 2014

Status

approved