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Search: id:A126986
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| A126986 |
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Expansion of 1/(1+4*x*c(x)), c(x) the g.f. of Catalan numbers A000108. |
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+0
5
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| 1, -4, 12, -40, 124, -408, 1272, -4176, 13020, -42808, 133096, -439344, 1358872, -4514800, 13853040, -46469280, 140945820, -479312760, 1430085000, -4958382960, 14453014920, -51500944080, 145230007440, -537922074720, 1446902948184, -5662012752048, 14228883685392
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Hankel transform is (-4)^n.
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FORMULA
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a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-5)^k.
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MAPLE
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c:=(1-sqrt(1-4*x))/2/x: ser:=series(1/(1+4*x*c), x=0, 30): seq(coeff(ser, x, n), n=0..27); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 23 2007
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CROSSREFS
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Sequence in context: A056274 A058353 A104525 this_sequence A090576 A152174 A087206
Adjacent sequences: A126983 A126984 A126985 this_sequence A126987 A126988 A126989
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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 23 2007
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