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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 1
0, 2346, 1435808, 886416182, 524266454832, 307860650044792, 180328865345987360, 105557191885030726384, 61776749660998923874410, 36152465383268281809542282, 21156493983680665465727818196 (list; graph; refs; listen; history; text; internal format)
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 A264943

Adjacent sequences:  A216986 A216987 A216988 * A216990 A216991 A216992

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 21 2012

STATUS

approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)