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A270612
Number of 7X7X7 triangular 0..n arrays with some element plus some adjacent element totalling n+1 or n-1 exactly once.
0
0, 0, 8708857332, 98204118828408, 9214293422949066, 4757551848002860896, 285369749616515150016, 32625021173112501378696, 1060574342507074466039772, 42481155976455567861014856
OFFSET
1,3
COMMENTS
Row 7 of A270606.
EXAMPLE
Some solutions for n=3
........0..............3..............3..............0..............0
.......3.3............1.0............3.0............3.3............0.0
......0.0.3..........0.0.0..........0.0.0..........0.0.3..........0.3.0
.....0.0.3.0........0.0.1.0........0.0.0.0........0.0.3.3........0.0.3.2
....0.0.0.3.3......0.0.0.0.0......0.0.0.3.3......0.0.0.0.2......0.0.0.3.3
...0.0.0.0.3.3....0.0.0.0.3.0....0.0.0.0.3.0....0.0.0.0.3.3....0.0.0.0.3.3
..0.0.0.0.0.0.2..0.0.0.0.0.3.0..0.0.0.0.1.0.0..0.0.0.0.0.3.2..0.0.0.0.3.3.3
CROSSREFS
Cf. A270606.
Sequence in context: A181746 A185429 A154876 * A331412 A204407 A144651
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 20 2016
STATUS
approved