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A091699 Row sums of triangle A091698. 3
1, 0, -1, 3, -9, 30, -109, 420, -1685, 6960, -29391, 126291, -550359, 2426502, -10803801, 48507843, -219377949, 998436792, -4569488371, 21016589073, -97090411019, 450314942682, -2096122733211, 9788916220518 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

COMMENTS

Hankel transform is (-1)^n. [From Paul Barry (pbarry(AT)wit.ie), Jun 17 2010]

FORMULA

G.f.: A(x) = 2/(3+3*x - sqrt(1+6*x+5*x^2)). - Paul D. Hanna (pauldhanna(AT)juno.com), Feb 23 2004

PROG

(PARI) a(n)=polcoeff(2/(3+3*x-sqrt(1+6*x+5*x^2+x*O(x^n))), n, x) (Paul Hanna)

CROSSREFS

Sequence in context: A099783 A200074 A032125 * A129167 A151472 A107379

Adjacent sequences:  A091696 A091697 A091698 * A091700 A091701 A091702

KEYWORD

sign

AUTHOR

Christian G. Bower (bowerc(AT)usa.net), Jan 29 2004

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Last modified February 16 11:47 EST 2012. Contains 205907 sequences.