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A202029
Number of nX4 zero-sum -1..1 arrays with rows and columns lexicographically nondecreasing
1
3, 56, 1341, 29363, 537572, 8249505, 108479344, 1248911674, 12812139620, 118772002152, 1006266126267, 7863720278445, 57120674129416, 388168845356086, 2481485055755353, 14994743673623870, 86001919259575522, 469898358909610160
OFFSET
1,1
COMMENTS
Column 4 of A202033
LINKS
EXAMPLE
Some solutions for n=4
.-1.-1.-1..1...-1.-1.-1..0...-1..0..0..1...-1..0..0..1...-1.-1.-1..0
.-1..0..1.-1....0..1..1.-1....0.-1..0.-1....0..0..0..1...-1..1..1..1
..1..1.-1..0....1.-1..0..0....1..1..0.-1....0..0..1.-1....0.-1..1.-1
..1..1..0..0....1..0..0..1....1..1..0.-1....1.-1.-1..0....0..1..1..0
CROSSREFS
Sequence in context: A263886 A160876 A241136 * A287396 A335804 A070731
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 09 2011
STATUS
approved