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A216984
Number of city-block distance 1, pressure limit 2 movements in an n X n array with each element moving exactly one horizontally or vertically, no element acquiring more than two neighbors, and without 2-loops
1
0, 2, 264, 280900, 2891592224, 307860650044792, 342045101062468307160, 3979259269110908593906417328, 485168384985330726560602698774047840, 620116995791586597194849424436942942331423388
OFFSET
1,2
COMMENTS
Diagonal of A216991
LINKS
EXAMPLE
Some solutions for n=3 (movement: 0=n 1=e 2=s 3=w)
..1..2..3....1..2..3....2..3..3....1..2..3....1..2..3....1..1..2....2..3..3
..2..2..3....0..3..2....1..2..0....1..1..0....0..3..3....0..2..3....2..0..3
..1..1..0....0..3..3....0..3..3....0..3..3....0..1..0....0..1..0....1..0..0
CROSSREFS
Sequence in context: A122862 A236437 A137105 * A007082 A135388 A238983
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 21 2012
STATUS
approved