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A227167
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The number of meandering curves of order n.
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1
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1, 1, 6, 8, 50, 72, 462, 696, 4536, 7030, 46310, 73188, 485914, 778946, 5202690, 8430992, 56579196, 92470194, 622945970, 1025114180, 6927964218, 11465054942, 77692142980, 129180293184, 877395996200, 1464716085664, 9968202968958, 16698145444260, 113837957337750, 191264779292430
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OFFSET
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1,3
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COMMENTS
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A meandering curve of order n is a continuous curve which does not intersect itself yet intersects a horizontal line n times.
The set of meandering curves of order n is partitioned into the following three classes: curves with no extremities (A005316), curves with only one extremity (A217310), and curves with both extremities covered by their arcs (A217318).
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REFERENCES
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A. Panayotopoulos and P. Tsikouras, Properties of meanders, JCMCC 46 (2003), 181-190.
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LINKS
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FORMULA
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a(n) = A000136(n) if n is odd and a(n) = (1/2)*A000136(n) if n is even.
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MATHEMATICA
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A000136 = Cases[Import["https://oeis.org/A000136/b000136.txt", "Table"], {_, _}][[All, 2]];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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