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A216832
Number of city-block distance 1 permutations of a side-n hexagonal array.
0
0, 36, 198576, 427073321712, 160091486928671945664
OFFSET
1,2
EXAMPLE
Some solutions for n=3 (movement: 0=nw 1=ne 2=e 3=se 4=sw 5=w)
...3.3.3.......2.5.3.......3.2.5.......3.2.3.......2.4.3
..1.1.1.3.....4.5.4.0.....4.0.4.3.....4.0.0.5.....3.0.4.0
.1.3.2.4.4...3.1.1.2.5...1.3.1.3.0...1.4.2.4.4...1.5.2.0.4
..0.0.0.4.....1.4.2.5.....3.0.4.0.....1.1.3.1.....3.2.5.1
...0.5.5.......1.2.5.......0.2.0.......1.5.5.......0.2.5
CROSSREFS
Sequence in context: A203270 A185960 A334409 * A013839 A271386 A065752
KEYWORD
nonn,hard,more
AUTHOR
R. H. Hardin Sep 17 2012
STATUS
approved