A216989 Number of city-block distance 1, pressure limit 2 movements in an nX6 array with each element moving exactly one horizontally or vertically, no element acquiring more than two neighbors, and without 2-loops

0, 2346, 1435808, 886416182, 524266454832, 307860650044792, 180328865345987360, 105557191885030726384, 61776749660998923874410, 36152465383268281809542282, 21156493983680665465727818196

Offset

1,2

Comments

Column 6 of A216991

Links

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

Example

Some solutions for n=3 (movement: 0=n 1=e 2=s 3=w)
..2..2..1..2..1..2....2..2..2..2..3..3....2..2..1..2..3..3....2..2..2..3..2..2
..2..2..3..3..2..3....2..3..1..2..0..0....2..2..3..2..2..2....2..1..1..0..3..3
..1..1..0..0..3..3....1..0..0..1..1..0....1..1..0..3..3..3....1..0..3..3..3..0

Crossrefs

Sequence in context: A064868 A263556 A255099 * A281697 A045306 A351229

Adjacent sequences: A216986 A216987 A216988 * A216990 A216991 A216992

Keyword

nonn

Author

R. H. Hardin Sep 21 2012

Status

approved