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 A197209 Row sums of A197208. 2
 3, 24, 180, 1320, 9660, 70896, 522648, 3871440, 28809990, 215318400, 1615579680, 12165491520, 91905439080, 696359055840, 5290416835440, 40291036122528, 307537305284574, 2352216447006480, 18024996856976760 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS Seiichi Manyama, Table of n, a(n) for n = 2..1000 FORMULA For n >= 2, a(n) = Sum_{k = 1..n-1} C(n-1,k-1)*C(n,k+1)*C(n+1,k), where C(n,k) = binomial(n,k). a(n) = (1/(n+2)) * ((7*n^2-7*n-2)*a(n-1)/(n-2) + 8*n*a(n-2)) for n > 3. - Seiichi Manyama, Jan 09 2021 MATHEMATICA Table[Sum[Binomial[n-1, k-1]Binomial[n, k+1]Binomial[n+1, k], {k, n-1}], {n, 2, 20}] (* Harvey P. Dale, May 08 2016 *) PROG (PARI) a(n) = sum(k=1, n-1, binomial(n-1, k-1)*binomial(n, k+1)*binomial(n+1, k)); \\ Michel Marcus, Jan 09 2021 CROSSREFS Cf. A007318, A197208. Sequence in context: A120741 A292293 A073985 * A317527 A181967 A144087 Adjacent sequences:  A197206 A197207 A197208 * A197210 A197211 A197212 KEYWORD nonn,easy AUTHOR Peter Bala, Oct 12 2011 STATUS approved

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Last modified January 25 08:59 EST 2021. Contains 340416 sequences. (Running on oeis4.)