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A127503
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Number of n X n matrices A with 1's on the main diagonal and -1's and 0's elsewhere such that A + A' has only 0's and -1's off the main diagonal and is positive semi-definite.
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2
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OFFSET
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1,2
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COMMENTS
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For number of different values of A + A' see A084553.
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LINKS
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CROSSREFS
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KEYWORD
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nonn,more,nice
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AUTHOR
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STATUS
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approved
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