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A194992
Number of lower triangles of an n X n 0..2 array with each element differing from all of its horizontal and vertical neighbors by one.
1
3, 6, 20, 80, 576, 4608, 69632, 1114112, 34603008, 1107296256, 69793218560, 4466765987840, 567347999932416, 72620543991349248, 18518801667747479552, 4740813226943354765312, 2422574005712127994626048
OFFSET
1,1
COMMENTS
Column 2 of A194998.
LINKS
EXAMPLE
Some solutions for 4 X 4
..2........1........0........2........0........0........0........0
..1.0......2.1......1.2......1.0......1.0......1.0......1.0......1.0
..2.1.2....1.2.1....0.1.0....2.1.2....2.1.0....0.1.0....2.1.0....2.1.0
..1.0.1.0..2.1.2.1..1.2.1.0..1.2.1.0..1.2.1.2..1.0.1.2..1.2.1.0..1.0.1.2
CROSSREFS
Cf. A194998.
Sequence in context: A123559 A334329 A162171 * A163881 A238474 A019017
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 07 2011
STATUS
approved