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A117372 Riordan array (1-3x,x(1-x)). 2
1, -3, 1, 0, -4, 1, 0, 3, -5, 1, 0, 0, 7, -6, 1, 0, 0, -3, 12, -7, 1, 0, 0, 0, -10, 18, -8, 1, 0, 0, 0, 3, -22, 25, -9, 1, 0, 0, 0, 0, 13, -40, 33, -10, 1, 0, 0, 0, 0, -3, 35, -65, 42, -11, 1, 0, 0, 0, 0, 0, -16, 75, -98, 52, -12, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Row sums are A117373. Diagonal sums are A117374. Inverse is A117375.

LINKS

Table of n, a(n) for n=0..65.

FORMULA

Number triangle T(n,k)=(-1)^(n-k)(C(k,n-k)+3*C(k, n-k-1))

EXAMPLE

Triangle begins

1,

-3, 1,

0, -4, 1,

0, 3, -5, 1,

0, 0, 7, -6, 1,

0, 0, -3, 12, -7, 1,

0, 0, 0, -10, 18, -8, 1,

0, 0, 0, 3, -22, 25, -9, 1

CROSSREFS

Sequence in context: A285123 A159059 A127569 * A127570 A292506 A212186

Adjacent sequences:  A117369 A117370 A117371 * A117373 A117374 A117375

KEYWORD

easy,sign,tabl

AUTHOR

Paul Barry, Mar 10 2006

STATUS

approved

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Last modified October 22 00:52 EDT 2019. Contains 328315 sequences. (Running on oeis4.)