A206408 Number of (n+1) X 3 0..2 arrays with every 2 X 3 or 3 X 2 subblock having an equal number of clockwise and counterclockwise edge increases.

423, 5199, 69585, 953865, 13148043, 181467207, 2505335985, 34591087977, 477605748651, 6594418668279, 91050821905233, 1257162198849945, 17357963791492635, 239665900404460215, 3309129149913889857

Offset

1,1

Comments

Column 2 of A206414.

Links

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

Formula

Empirical: a(n) = 19*a(n-1) - 78*a(n-2) + 86*a(n-3) + 17*a(n-4) - 41*a(n-5) + 10*a(n-6).

Empirical g.f.: 3*x*(141 - 946*x + 1266*x^2 + 298*x^3 - 689*x^4 + 170*x^5) / ((1 - 3*x - x^2 + x^3)*(1 - 16*x + 31*x^2 - 10*x^3)). - Colin Barker, Jun 16 2018

Example

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

Crossrefs

Cf. A206414.

Sequence in context: A205980 A206662 A205831 * A238174 A251013 A230678

Adjacent sequences: A206405 A206406 A206407 * A206409 A206410 A206411

Keyword

nonn

Author

R. H. Hardin, Feb 07 2012

Status

approved