A109963 - OEIS

A109963

Diagonal sums of number triangle A109962.

1, -1, 5, -27, 171, -1178, 8582, -65029, 507317, -4047608, 32874104, -270893586, 2259210814, -19032956491, 161735556091, -1384662302187, 11931865642979, -103409449621325, 900778907303037, -7882176975668156, 69253864680597564, -610717827031587856

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..21.

FORMULA

G.f.: g/(1-f) where f/(1-f)^4=x and g=1/(1-f); a(n)=(-1)^n*sum{k=0..floor(n/2), ((4k+1)/(3n-2k+1))*binomial(4n-4k, n-2k)}.

CROSSREFS

Sequence in context: A082425 A202248 A225344 * A201870 A091101 A185622

Adjacent sequences: A109960 A109961 A109962 * A109964 A109965 A109966

KEYWORD

easy,sign

AUTHOR

Paul Barry, Jul 06 2005

STATUS

approved