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Search: id:A126984
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| A126984 |
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Expansion of 1/(1+2*x*c(x)), c(x) the g.f. of Catalan numbers A000108. |
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+0
5
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| 1, -2, 2, -4, 2, -12, -12, -72, -190, -700, -2308, -8120, -28364, -100856, -360792, -1301904, -4727358, -17268636, -63405012, -233885784, -866327748, -3220976616, -12016209192, -44966763504, -168750724428, -634935132312, -2394717424552, -9051945482032
(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 (-2)^n.
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FORMULA
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a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-3)^k.
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MAPLE
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c:=(1-sqrt(1-4*x))/2/x: ser:=series(1/(1+2*x*c), x=0, 32): seq(coeff(ser, x, n), n=0..30); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 24 2007
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CROSSREFS
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Sequence in context: A067228 A010026 A059427 this_sequence A159749 A102416 A129243
Adjacent sequences: A126981 A126982 A126983 this_sequence A126985 A126986 A126987
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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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Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 24 2007
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