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A126987 Expansion of 1/(1+5*x*c(x)), c(x) the g.f. of Catalan numbers A000108. 6
1, -5, 20, -85, 350, -1470, 6090, -25485, 105830, -442150, 1838240, -7673330, 31923220, -133186760, 554325750, -2311919325, 9624918150, -40133290350, 167114005800, -696706389750, 2901470571300, -12094930814100, 50375156502900, -209972720898450, 874600454065500 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Hankel transform is (-5)^n.

LINKS

Table of n, a(n) for n=0..24.

FORMULA

a(n)=Sum_{k, 0<=k<=n}A039599(n,k)*(-6)^k.

MAPLE

c:=(1-sqrt(1-4*x))/2/x: ser:=series(1/(1+5*x*c), x=0, 27): seq(coeff(ser, x, n), n=0..24); - Emeric Deutsch, Mar 23 2007

CROSSREFS

Sequence in context: A099949 A006231 A069007 * A152185 A152187 A045499

Adjacent sequences:  A126984 A126985 A126986 * A126988 A126989 A126990

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 February 20 14:37 EST 2018. Contains 299380 sequences. (Running on oeis4.)