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A195517
Number of lower triangles of an n X n -3..3 array with all row and column sums zero
0
1, 1, 7, 175, 27267, 23663523, 122092290831, 3806404472713603, 731708552185212577507
OFFSET
1,3
COMMENTS
Column 3 of A195522
EXAMPLE
Some solutions for n=4
..0........0........0........0........0........0........0........0
.-1.1......0.0......2-2......0.0.....-3.3.....-2.2.....-2.2......2-2
.-2-1.3....2-2.0....1.0-1....3.0-3....3-3.0....0-3.3....0-3.3....0.1-1
..3.0-3.0.-2.2.0.0.-3.2.1.0.-3.0.3.0..0.0.0.0..2.1-3.0..2.1-3.0.-2.1.1.0
CROSSREFS
Sequence in context: A094257 A195887 A162082 * A239575 A152930 A027489
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 20 2011
STATUS
approved