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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. Equals B^(-1)*A097805, where B is the binomial matrix. LINKS 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; MATHEMATICA (* The function RiordanArray is defined in A256893. *) rows = 12; R = RiordanArray[1/(1 + #)&, #&, rows]; R // Flatten (* Jean-François Alcover, Jul 20 2019 *) 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 Cf. A008619, A059841, A097805, A097806. 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 October 14 00:32 EDT 2019. Contains 327991 sequences. (Running on oeis4.)