A209945 Half the number of (n+1)X3 0..2 arrays with every 2X2 subblock having at most one duplicate clockwise edge difference

258, 4975, 95794, 1845126, 35537484, 684469520, 13183187396, 253914272972, 4890505660356, 94193393412380, 1814208180084540, 34942486067121236, 673008393916430500, 12962452003109036652, 249662802833380927452

Offset

1,1

Comments

Column 2 of A209951

Links

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

Formula

Empirical: a(n) = 20*a(n-1) +25*a(n-2) -708*a(n-3) -1034*a(n-4) +2172*a(n-5) -160*a(n-6) -320*a(n-7)

Example

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

Crossrefs

Sequence in context: A252264 A202892 A158230 * A233306 A282060 A301546

Adjacent sequences: A209942 A209943 A209944 * A209946 A209947 A209948

Keyword

nonn

Author

R. H. Hardin Mar 16 2012

Status

approved