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A109963
Diagonal sums of number triangle A109962.
1
1, -1, 5, -27, 171, -1178, 8582, -65029, 507317, -4047608, 32874104, -270893586, 2259210814, -19032956491, 161735556091, -1384662302187, 11931865642979, -103409449621325, 900778907303037, -7882176975668156, 69253864680597564, -610717827031587856
OFFSET
0,3
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
KEYWORD
easy,sign
AUTHOR
Paul Barry, Jul 06 2005
STATUS
approved