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A006077
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(n+1)^2*a(n+1)=(9n^2+9n+3)a(n)-27*n^2*a(n-1).
(Formerly M2775)
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1
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1, 3, 9, 21, 9, -297, -2421, -12933, -52407, -145293, -35091, 2954097, 25228971, 142080669, 602217261, 1724917221, 283305033, -38852066421, -337425235479, -1938308236731, -8364863310291, -24286959061533, -3011589296289
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Comment from Matthijs Coster, Apr 28, 2004: This is the Taylor expansion of a special point on a curve described by Beauville.
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REFERENCES
| Arnaud Beauville, Les familles stables de courbes sur P_1 admettant quatre fibres singulieres, Comptes Rendus, Academie Science Paris, no. 294, May 24 1982.
Matthijs Coster, Over 6 families van krommen [On 6 families of curves], Master's Thesis (unpublished), Aug 26 1983.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| G.f.: hypergeom([1/3, 2/3],[1],x^3/(x-1/3)^3)/(1-3*x) - Mark van Hoeij, Oct 25 2011.
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PROG
| (PARI) subst(eta(q)^3/eta(q^3), q, serreverse(eta(q^9)^3/eta(q)^3*q)) (generating function) [From Helena Verrill (verrill(AT)math.lsu.edu), Apr 20 2009]
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CROSSREFS
| Sequence in context: A146219 A197403 A128127 * A109612 A032668 A050839
Adjacent sequences: A006074 A006075 A006076 * A006078 A006079 A006080
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KEYWORD
| sign
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from Kok Seng Chua (chuaks(AT)ihpc.nus.edu.sg), Jun 20 2000
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