A206679 Number of (n+1) X 3 0..2 arrays with every 2 X 3 or 3 X 2 subblock having an unequal number of clockwise and counterclockwise edge increases.

306, 1728, 9792, 55836, 317736, 1809324, 10300608, 58646916, 333899064, 1901032092, 10823363424, 61621963812, 350839639224, 1997477224380, 11372475138624, 64748269110564, 368639041055544, 2098816612656732

Offset

1,1

Comments

Column 2 of A206685.

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 13*a(n-2) + 11*a(n-3) + 12*a(n-4) + 6*a(n-5) for n>6.

Empirical g.f.: 18*x*(17 + 45*x + 35*x^2 + 35*x^3 + 14*x^4 - 2*x^5) / (1 - 3*x - 13*x^2 - 11*x^3 - 12*x^4 - 6*x^5). - Colin Barker, Jun 17 2018

Example

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

Crossrefs

Cf. A206685.

Sequence in context: A236012 A158589 A030030 * A172966 A223073 A064257

Adjacent sequences: A206676 A206677 A206678 * A206680 A206681 A206682

Keyword

nonn

Author

R. H. Hardin, Feb 11 2012

Status

approved