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A007137
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Number of rooted maps with n edges on the projective plane.
(Formerly M4734)
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2
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1, 10, 98, 982, 10062, 105024, 1112757, 11934910, 129307100, 1412855500, 15548498902, 172168201088, 1916619748084, 21436209373224, 240741065193282, 2713584138389838, 30687358107371442, 348061628432108352
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| E. A. Bender, E. R. Canfield and R. W. Robinson, The enumeration of maps on the torus and the projective plane, Canad. Math. Bull., 31 (1988), 257-271.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..100
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FORMULA
| G.f.: ((2*R+1)/3-sqrt(R*(R+2)/3))/(2*x) where R=sqrt(1-12*x); a(n) is asymptotic to sqrt(3/2)*12^n/(n^(5/4)*GAMMA(3/4)) - Pab Ter (pabrlos2(AT)yahoo.com), Nov 07 2005
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MAPLE
| R:=sqrt(1-12*x): seq(coeff(convert(series(((2*R+1)/3-sqrt(R*(R+2)/3))/(2*x), x, 50), polynom), x, n), n=1..25); (Pab Ter)
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CROSSREFS
| Cf. A006300.
Sequence in context: A125445 A163446 A190869 * A135927 A129542 A171315
Adjacent sequences: A007134 A007135 A007136 * A007138 A007139 A007140
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KEYWORD
| nonn,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Reference gives 20 terms.
Description corrected May 15 1997 - thanks to Jean-Francois Beraud.
More terms from Pab Ter (pabrlos2(AT)yahoo.com), Nov 07 2005
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