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A261603
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Number of permutations of the set {1,2,...,n}^2 such that first coordinates of first floor(n^2/2) elements are nondecreasing and second coordinates of the remaining ceiling(n^2/2) elements are nondecreasing.
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1
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1, 10, 1944, 15858432, 7763310604800, 338060641751949312000, 1761952269949978269865476096000, 1455735772788406631491292993098686136320000, 241478064611792629237655079290406479536142910750720000000, 10017186663047806334488985920024892176911305625097432121928056832000000000
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OFFSET
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1,2
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LINKS
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FORMULA
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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