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A097807 Riordan array (1/(1+x),1) read by rows. 11
1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Columns have g.f. x^k/(1+x). Row sums are A059841. Diagonal sums are (-1)^n*A008619 with g.f. 1/((1+x)(1-x^2)). Inverse of A097806. A097807=B^(-1)*A097805, where B is the binomial matrix.

LINKS

Table of n, a(n) for n=0..80.

FORMULA

Triangle array of numbers T(n, k) with T(n, k)=if(n>=k, (-1)^(n-k), 0).

T(n+1,0) = -T(n,0), T(n+1,k+1) = T(n,k) for k = 1..n. - Reinhard Zumkeller, Sep 17 2014

EXAMPLE

Rows begin

1;

-1,1;

1,-1,1;

-1,1,-1,1;

1,-1,1,-1,1;

PROG

(Haskell)

a097807 n k = a097807_tabl !! n !! k

a097807_row n = a097807_tabl !! n

a097807_tabl = iterate(\xs@(x:_) -> - x : xs) [1]

-- Reinhard Zumkeller, Sep 17 2014

CROSSREFS

Sequence in context: A244513 A020985 A034947 * A014077 A174351 A181432

Adjacent sequences:  A097804 A097805 A097806 * A097808 A097809 A097810

KEYWORD

easy,sign,tabl

AUTHOR

Paul Barry, Aug 25 2004

STATUS

approved

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Last modified February 16 21:59 EST 2019. Contains 320200 sequences. (Running on oeis4.)