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Search: id:A069730
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| A069730 |
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Number of nonisomorphic unrooted unicursal planar maps with n edges. |
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+0
1
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| 1, 2, 4, 13, 50, 248, 1407, 8600, 55154, 365292, 2473956, 17053468, 119191992, 842688120, 6015275094, 43292026736, 313788095994, 2288506113056, 16781638172458, 123656774440396, 915123392599456
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Unicursal (in a broad sense) means that no more than two vertices are of odd valency (that is maps possessing an Eulerian path).
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REFERENCES
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V. A. Liskovets and T. R. S. Walsh, Enumeration of Eulerian and unicursal planar maps, Discr. Math., 282 (2004), 209-221.
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FORMULA
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a(n)=A069727(n)+A069724(n)
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CROSSREFS
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Cf. A069727, A069724.
Sequence in context: A153930 A005164 A058134 this_sequence A072605 A030953 A030811
Adjacent sequences: A069727 A069728 A069729 this_sequence A069731 A069732 A069733
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KEYWORD
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easy,nonn
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AUTHOR
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Valery A. Liskovets (liskov(AT)im.bas-net.by), Apr 07 2002
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