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A069730 Number of nonisomorphic unrooted unicursal planar maps with n edges. +0
1
1, 2, 4, 13, 50, 248, 1407, 8600, 55154, 365292, 2473956, 17053468, 119191992, 842688120, 6015275094, 43292026736, 313788095994, 2288506113056, 16781638172458, 123656774440396, 915123392599456 (list; graph; listen)
OFFSET

0,2

COMMENT

Unicursal (in a broad sense) means that no more than two vertices are of odd valency (that is maps possessing an Eulerian path).

REFERENCES

V. A. Liskovets and T. R. S. Walsh, Enumeration of Eulerian and unicursal planar maps, Discr. Math., 282 (2004), 209-221.

FORMULA

a(n)=A069727(n)+A069724(n)

CROSSREFS

Cf. A069727, A069724.

Sequence in context: A153930 A005164 A058134 this_sequence A072605 A030953 A030811

Adjacent sequences: A069727 A069728 A069729 this_sequence A069731 A069732 A069733

KEYWORD

easy,nonn

AUTHOR

Valery A. Liskovets (liskov(AT)im.bas-net.by), Apr 07 2002

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.


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