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A006295
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Number of genus 1 rooted maps with 2 faces with n vertices
(Formerly M4739)
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11
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10, 167, 1720, 14065, 100156, 649950, 3944928, 22764165, 126264820, 678405090, 3550829360, 18182708362, 91392185080, 452077562620, 2205359390592, 10627956019245, 50668344988068, 239250231713210, 1120028580999440, 5202779260636958, 23998704563581000, 109991785264412452, 501177338394193600, 2271383798432172450, 10243348296746854536, 45984242301056376660, 205559341637958057568, 915285296612144724660, 4060537494602836978160, 17952439453856255549176, 79117286081659327659520
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OFFSET
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3,1
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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).
T. R. S. Walsh, Combinatorial Enumeration of Non-Planar Maps. Ph.D. Dissertation, Univ. of Toronto, 1971.
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LINKS
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FORMULA
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G.f.: x(1-sqrt(1-4*x))(11+12*x+9*sqrt(1-4*x))/(4(4*x-1)^4). - Sean A. Irvine, Nov 14 2010
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MATHEMATICA
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Rest[CoefficientList[Series[(1 - Sqrt[1 - 4 x]) (11 + 12 x + 9 Sqrt[1 - 4 x]) / (4 (4 x - 1)^4), {x, 0, 40}], x]] (* Vincenzo Librandi, Jun 06 2017 *)
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PROG
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(PARI)
A000108_ser(N) = my(x='x+O('x^(N+1))); (1 - sqrt(1-4*x))/(2*x);
my(y = A000108_ser(N+1)); y*(y-1)^3*(y^2 + 15*y - 6)/(y-2)^8;
};
(PARI) x = 'x + O('x^60); Vec(x*(1-sqrt(1-4*x))*(11+12*x+9*sqrt(1-4*x))/(4*(4*x-1)^4)) \\ Michel Marcus, Jun 05 2017
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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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STATUS
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approved
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