A233083 Number of 2 X n 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 in row major order.

3, 14, 95, 662, 4631, 32414, 226895, 1588262, 11117831, 77824814, 544773695, 3813415862, 26693911031, 186857377214, 1308001640495, 9156011483462, 64092080384231, 448644562689614, 3140511938827295, 21983583571791062

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-1) - 7*a(n-2) for n>3.

Conjectures from Colin Barker, Oct 07 2018: (Start)

G.f.: x*(3 - 10*x + 4*x^2) / ((1 - x)*(1 - 7*x)).

a(n) = (49 + 27*7^n) / 98 for n>1.

(End)

Example

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

Crossrefs

Row 2 of A233082.

Sequence in context: A214378 A094369 A005772 * A053984 A113181 A295105

Adjacent sequences: A233080 A233081 A233082 * A233084 A233085 A233086

Keyword

nonn

Author

R. H. Hardin, Dec 03 2013

Status

approved