A202883 Number of n X 2 0..2 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.

3, 35, 265, 1849, 13345, 96941, 701275, 5071167, 36689027, 265439091, 1920308033, 13892446697, 100505282121, 727107537885, 5260271847715, 38055531396239, 275313438949691, 1991760080088995, 14409424470217081, 104245243244589977

Offset

1,1

Comments

Column 2 of A202889.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) +2*a(n-2) +46*a(n-3) +25*a(n-4) +36*a(n-5).

Empirical g.f.: (3 + 17*x + 49*x^2 + 51*x^3 + 36*x^4) / (1 - 6*x - 2*x^2 - 46*x^3 - 25*x^4 - 36*x^5). - Colin Barker, Jun 02 2018

Example

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

Crossrefs

Cf. A202889.

Sequence in context: A061548 A019273 A271209 * A069448 A339516 A121078

Adjacent sequences: A202880 A202881 A202882 * A202884 A202885 A202886

Keyword

nonn

Author

R. H. Hardin, Dec 25 2011

Status

approved