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A332415
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a(n) is the number of distinct valid solutions taking into account the ambiguity of open and closed absolute value bars for an input of -1 to -2*(n)-1 with absolute value bars between each (|-1|, |-1|-2|-3|, |-1|-2|-3|-4|-5|, etc.).
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0
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1, 2, 5, 13, 39, 124, 403, 1304, 4301, 14370, 47575, 157153, 512311, 1663977, 5446573
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OFFSET
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1,2
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COMMENTS
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a(5) is the solution to Jim Propp's submitted problem published in FiveThirtyEight's "The Riddler" column.
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LINKS
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EXAMPLE
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For n = 2 (input of |-1|-2|-3|-4|-5|) the solutions are 5 and -5, so a(2) = 2.
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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