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A006445
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Number of n-edge 3-connected planar maps with a sense-reversing automorphism.
(Formerly M0172)
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0
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0, 0, 0, 0, 0, 1, 0, 1, 2, 1, 4, 9, 12, 27, 50, 99, 188, 386, 740, 1528, 3012, 6192, 12376, 25594, 51628, 107135, 218100, 453895, 930812, 1943281, 4009512, 8394915, 17414512
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OFFSET
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1,9
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COMMENTS
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Maps are counted up to isomorphism which is not restricted to those that preserve the orientation of the sphere.
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
Computed by Nick Wormald (unpublished).
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LINKS
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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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