A234491 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 (constant-stress 1 X 1 tilings).

250, 1834, 13464, 99142, 728536, 5368636, 39476802, 291119578, 2142048610, 15807820384, 116387461374, 859523654392, 6332338846996, 46797181439986, 344979511889562, 2551214650069978, 18818390917298920, 139260488424222934

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) + 74*a(n-2) - 295*a(n-3) - 1008*a(n-4) + 840*a(n-5).

Empirical g.f.: 2*x*(125 + 292*x - 7103*x^2 - 15072*x^3 + 14760*x^4) / ((1 - 56*x^2)*(1 - 5*x - 18*x^2 + 15*x^3)). - Colin Barker, Oct 15 2018

Example

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

Crossrefs

Column 1 of A234497.

Sequence in context: A045185 A122270 A234497 * A249199 A249214 A249321

Adjacent sequences: A234488 A234489 A234490 * A234492 A234493 A234494

Keyword

nonn

Author

R. H. Hardin, Dec 26 2013

Status

approved