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Search: id:A126985
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| A126985 |
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Expansion of 1/(1+8*x*c(x)), c(x) the g.f. of Catalan numbers A000108. |
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+0
5
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| 1, -8, 56, -400, 2840, -20208, 143664, -1021728, 7265240, -51665200, 367392656, -2612584928, 18578329456, -132112749920, 939467783520, -6680662171200, 47506922377560, -337827035002800, 2402325467002320, -17083203745473120, 121480558396908240, -863861754435010080
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OFFSET
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0,2
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COMMENT
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Hankel transform is (-8)^n.
Catalan transform of (-1)^n*A001018(n). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 11 2008]
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FORMULA
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a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-9)^k.
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MAPLE
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c:=(1-sqrt(1-4*x))/2/x: ser:=series(1/(1+8*x*c), x=0, 25): seq(coeff(ser, x, n), n=0..21); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 24 2007
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CROSSREFS
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Sequence in context: A063812 A003950 A033134 this_sequence A027081 A093134 A001398
Adjacent sequences: A126982 A126983 A126984 this_sequence A126986 A126987 A126988
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KEYWORD
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sign
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Mar 21 2007
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 24 2007
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