A278183 Number of n X 2 0..3 arrays with every element plus 1 mod 4 equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) or (1,0), with upper left element zero.

0, 3, 28, 200, 1532, 11794, 90538, 695252, 5339294, 41003018, 314882364, 2418138526, 18570087298, 142608927356, 1095164819630, 8410314860218, 64586987065356, 495995568270926, 3808996439085090, 29251176423848812

Offset

1,2

Links

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

Formula

Empirical: a(n) = 8*a(n-1) - 4*a(n-2) + 15*a(n-3) - 26*a(n-4) + 14*a(n-5) - 16*a(n-6).

Empirical g.f.: x^2*(3 + 4*x - 12*x^2 - x^3 - 4*x^4) / (1 - 8*x + 4*x^2 - 15*x^3 + 26*x^4 - 14*x^5 + 16*x^6). - Colin Barker, Feb 08 2019

Example

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

Crossrefs

Column 2 of A278188.

Sequence in context: A081019 A241455 A356975 * A091120 A045737 A003466

Adjacent sequences: A278180 A278181 A278182 * A278184 A278185 A278186

Keyword

nonn

Author

R. H. Hardin, Nov 14 2016

Status

approved