A232943 Number of nX3 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, vertically or antidiagonally, and top left element zero

9, 99, 1163, 13707, 161621, 1905737, 22471303, 264968059, 3124343613, 36840376337, 434399508111, 5122177116787, 60397624596373, 712172377821369, 8397507337767063, 99018343990785067, 1167564617964899501

Offset

1,1

Comments

Column 3 of A232948

Links

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

Formula

Empirical: a(n) = 13*a(n-1) -15*a(n-2) +9*a(n-3) -2*a(n-4) for n>5.

Empirical: g.f. 9*x -x*(-99+124*x-73*x^2+16*x^3) / ( 1-13*x+15*x^2-9*x^3+2*x^4 ). - R. J. Mathar, Nov 27 2015

Example

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

Crossrefs

Sequence in context: A002283 A155157 A264005 * A245927 A233907 A294120

Adjacent sequences: A232940 A232941 A232942 * A232944 A232945 A232946

Keyword

nonn

Author

R. H. Hardin, Dec 02 2013

Status

approved