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 A110517 Riordan array (1,x(1-3x)). 6
 1, 0, 1, 0, -3, 1, 0, 0, -6, 1, 0, 0, 9, -9, 1, 0, 0, 0, 27, -12, 1, 0, 0, 0, -27, 54, -15, 1, 0, 0, 0, 0, -108, 90, -18, 1, 0, 0, 0, 0, 81, -270, 135, -21, 1, 0, 0, 0, 0, 0, 405, -540, 189, -24, 1, 0, 0, 0, 0, 0, -243, 1215, -945, 252, -27, 1, 0, 0, 0, 0, 0, 0, -1458, 2835, -1512, 324, -30, 1, 0, 0, 0, 0, 0, 0, 729, -5103, 5670, -2268, 405 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS Inverse is Riordan array (1,xc(3x)) [A110518]. Row sums are A106852. Diagonal sums are A106855. Modulo 2, this sequence becomes A106344. - Philippe Deléham, Dec 19 2008 LINKS G. C. Greubel, Table of n, a(n) for the first 50 rows, flattened FORMULA Number triangle: T(n, k) = (-3)^(n-k)*binomial(k, n-k). T(n,k) = A109466(n,k)*3^(n-k). - Philippe Deléham, Oct 26 2008 EXAMPLE Rows begin 1; 0, 1; 0, -3, 1; 0, 0, -6, 1; 0, 0, 9, -9, 1; 0, 0, 0, 27, -12, 1; 0, 0, 0, -27, 54, -15, 1; MATHEMATICA T[n_, k_] := (-3)^(n - k)*Binomial[k, n - k]; Table[T[n, k], {n, 0, 20}, {k, 0, n}] // Flatten (* G. C. Greubel, Aug 29 2017 *) PROG (PARI) for(n=0, 20, for(k=0, n, print1((-3)^(n-k)*binomial(k, n-k), ", "))) \\ G. C. Greubel, Aug 29 2017 CROSSREFS Sequence in context: A115090 A112295 A318973 * A091925 A034370 A144402 Adjacent sequences:  A110514 A110515 A110516 * A110518 A110519 A110520 KEYWORD easy,sign,tabl AUTHOR Paul Barry, Jul 24 2005 STATUS approved

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Last modified October 23 11:48 EDT 2019. Contains 328345 sequences. (Running on oeis4.)