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A126984 Expansion of 1/(1+2*x*c(x)), c(x) the g.f. of Catalan numbers A000108. 5
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; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Hankel transform is (-2)^n.

LINKS

Table of n, a(n) for n=0..27.

FORMULA

a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-3)^k.

MAPLE

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, Mar 24 2007

CROSSREFS

Sequence in context: A010026 A059427 A137777 * A159749 A227293 A102416

Adjacent sequences:  A126981 A126982 A126983 * A126985 A126986 A126987

KEYWORD

sign

AUTHOR

Philippe Deléham, Mar 21 2007

EXTENSIONS

Corrected and extended by Emeric Deutsch, Mar 24 2007

STATUS

approved

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Last modified October 19 00:36 EDT 2018. Contains 316327 sequences. (Running on oeis4.)