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A126986 Expansion of 1/(1+4*x*c(x)), c(x) the g.f. of Catalan numbers A000108. 5
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; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Hankel transform is (-4)^n.

LINKS

Table of n, a(n) for n=0..26.

FORMULA

a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-5)^k.

MAPLE

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, Mar 23 2007

CROSSREFS

Sequence in context: A056274 A058353 A104525 * A090576 A152174 A087206

Adjacent sequences:  A126983 A126984 A126985 * A126987 A126988 A126989

KEYWORD

sign

AUTHOR

Philippe Deléham, Mar 21 2007

EXTENSIONS

More terms from Emeric Deutsch, Mar 23 2007

STATUS

approved

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Last modified November 19 14:52 EST 2018. Contains 317352 sequences. (Running on oeis4.)