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A061162
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a(n) = (6n)!n!/((3n)!(2n)!^2).
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3
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1, 30, 2310, 204204, 19122246, 1848483780, 182327718300, 18236779032600, 1842826521244230, 187679234340049620, 19232182592635611060, 1980665038436368775400, 204826599735691440534300
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| According to page 781 of the cited reference the generating function F(x) for a(n) is algebraic but not obviously so and the minimal polynomial satisfied by F(x) is quite large.
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REFERENCES
| M. Kontsevich and D. Zagier, Periods, in Mathematics Unlimited - 2001 and Beyond, Springer, Berlin, 2001, pp. 771-808.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=0,...,100
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FORMULA
| a(n) ~ 1/2*pi^(-1/2)*n^(-1/2)*2^(2*n)*3^(3*n)*{1 - 1/72*n^-1 + ...} - Joe Keane (jgk(AT)jgk.org), Jun 11 2002
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MAPLE
| A061162 := n->(6*n)!*n!/((3*n)!*(2*n)!^2);
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PROG
| (PARI) { for (n=0, 100, write("b061162.txt", n, " ", (6*n)!*n!/((3*n)!*(2*n)!^2)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 18 2009]
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CROSSREFS
| Cf. A061163, A061164.
See also A091527.
Sequence in context: A056093 A056070 A054647 * A138916 A091544 A108091
Adjacent sequences: A061159 A061160 A061161 * A061163 A061164 A061165
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KEYWORD
| easy,nonn
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AUTHOR
| R. P. Stanley (rstan(AT)math.mit.edu), Apr 17 2001
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Apr 19 2001
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