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A064049
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Number of possible arrangements of numbers 1 to n*(n+1)/2 in a triangle of n rows so that each row and each diagonal is increasing or decreasing.
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2
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OFFSET
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1,2
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LINKS
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EXAMPLE
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The following triangle of 4 rows satisfies the requirements:
....1
...3 2
..4 5 8
.6 7 9 10
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CROSSREFS
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KEYWORD
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more,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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