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A006432
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Number of tree-rooted planar maps with 3 vertices and n faces and no isthmuses.
(Formerly M3166)
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2
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0, 3, 60, 650, 5352, 37681, 239752, 1421226, 7996160, 43219990, 226309800, 1154900708, 5769562736, 28312118565, 136830224464, 652656300122, 3077631550512, 14367512295274, 66478236840680, 305161336656876, 1390869368495728, 6298727501142218, 28358908010334960
(list;
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listen;
history;
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internal format)
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OFFSET
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1,2
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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).
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LINKS
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FORMULA
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a(n) seems to be divisible by n+1. - Ralf Stephan, Sep 01 2003
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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Name clarified and terms a(13) and beyond from Andrew Howroyd, Apr 06 2021
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STATUS
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approved
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