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Search: id:A000184
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| A000184 |
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Number of rooted planar maps with n edges.
(Formerly M2128 N0843)
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+0
2
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| 2, 22, 164, 1030, 5868, 31388, 160648, 795846, 3845020, 18211380, 84876152, 390331292, 1775032504
(list; graph; listen)
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OFFSET
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2,1
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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).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
Tutte, W. T.; On the enumeration of planar maps. Bull. Amer. Math. Soc. 74 1968 64-74.
T. R. S. Walsh, Combinatorial Enumeration of Non-Planar Maps. Ph.D. Dissertation, Univ. of Toronto, 1971.
T. R. S. Walsh and A. B. Lehman, Counting rooted maps by genus, J. Comb. Thy B13 (1972), 122-141 and 192-218.
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LINKS
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Richard P. Stanley, CATALAN ADDENDUM, version of Jul 19, 2008, p. 24. [From Jonathan Vos Post (jvospost3(AT)gmail.com), Aug 16 2008]
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FORMULA
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Appears to be 2 * A029887(n). - R. Stephan, Aug 17 2004
a(n) = (2 * (2*n)! * 3^n)/(n! * (n+1)!) = ((2*(3^n))/(n+2))*C(n) where C(n) is the n-th Catalan number, A000108(n). [From Jonathan Vos Post (jvospost3(AT)gmail.com), Aug 16 2008]
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CROSSREFS
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Sequence in context: A067057 A123960 A091169 this_sequence A007613 A043037 A058441
Adjacent sequences: A000181 A000182 A000183 this_sequence A000185 A000186 A000187
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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