A210070 1/4 the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having one or three distinct clockwise edge differences.

33, 313, 2908, 27129, 252951, 2358878, 21997263, 205132657, 1912938102, 17838863745, 166354085323, 1551314182238, 14466586111383, 134906337113945, 1258052152683182, 11731807807607937, 109403504572460163

Offset

1,1

Comments

Column 1 of A210077.

Links

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

Formula

Empirical: a(n) = 9*a(n-1) + 9*a(n-2) - 50*a(n-3) - 54*a(n-4) + 12*a(n-5) + 16*a(n-6).

Empirical g.f.: x*(33 + 16*x - 206*x^2 - 210*x^3 + 50*x^4 + 64*x^5) / (1 - 9*x - 9*x^2 + 50*x^3 + 54*x^4 - 12*x^5 - 16*x^6). - Colin Barker, Jul 14 2018

Example

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

Crossrefs

Cf. A210077.

Sequence in context: A256109 A241966 A210077 * A258638 A081932 A121994

Adjacent sequences: A210067 A210068 A210069 * A210071 A210072 A210073

Keyword

nonn

Author

R. H. Hardin, Mar 17 2012

Status

approved