A235275 Number of (n+1) X (5+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).

1120, 1660, 2344, 3952, 6232, 11704, 20440, 41704, 79480, 172360, 352024, 797512, 1714552, 4006024, 8930200, 21319624, 48718840, 118055560, 274305304, 671516872, 1577623672, 3888983944, 9203383960, 22793395144, 54200318200, 134655258760

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*(280 + 135*x - 4029*x^2 - 1623*x^3 + 20405*x^4 + 6138*x^5 - 43086*x^6 - 7344*x^7 + 31824*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:
  1 4 0 3 0 3    1 3 2 4 0 3    3 1 3 1 3 0    0 3 0 3 0 4
  3 1 2 0 2 0    3 0 4 1 2 0    1 4 1 4 1 3    4 2 4 2 4 3
  1 4 0 3 0 3    1 3 2 4 0 3    4 2 4 2 4 1    0 3 0 3 0 4
  3 1 2 0 2 0    3 0 4 1 2 0    0 3 0 3 0 2    2 0 2 0 2 1
  1 4 0 3 0 3    1 3 2 4 0 3    4 2 4 2 4 1    0 3 0 3 0 4

Crossrefs

Column 5 of A235280.

Sequence in context: A145334 A134211 A171004 * A235314 A340790 A237689

Adjacent sequences: A235272 A235273 A235274 * A235276 A235277 A235278

Keyword

nonn

Author

R. H. Hardin, Jan 05 2014

Status

approved