A205020 Number of (n+1)X2 0..3 arrays with the determinants of 2X2 subblocks nondecreasing rightwards and downwards

256, 2338, 15040, 84899, 456043, 2470216, 13615376, 76027865, 427451825, 2411941887, 13634285159, 77146583419, 436735262905, 2473069283987, 14006039121985, 79328088635035, 449320047871193, 2545034872510264

Offset

1,1

Comments

Column 1 of A205027

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -15*a(n-2) -41*a(n-3) +120*a(n-4) -72*a(n-5) for n>21

Example

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

Crossrefs

Sequence in context: A205635 A205027 A207300 * A204309 A235416 A235261

Adjacent sequences: A205017 A205018 A205019 * A205021 A205022 A205023

Keyword

nonn

Author

R. H. Hardin Jan 21 2012

Status

approved