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 A098401 a(n) = (0^n + 3^n*binomial(2n,n))/2. 2
 1, 3, 27, 270, 2835, 30618, 336798, 3752892, 42220035, 478493730, 5454828522, 62482581252, 718549684398, 8290957896900, 95938227092700, 1112883434275320, 12937269923450595, 150681143814306930, 1757946677833580850, 20540219077844997300, 240320563210786468410 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS A098401(n+1)=3*A098399(n). LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..900 FORMULA G.f.: 6x/(sqrt(1-12x)(1-sqrt(1-12x)). n*a(n) +6*(-2*n+1)*a(n-1)=0. - R. J. Mathar, Nov 24 2012 PROG (MAGMA) [(0^n + 3^n * Binomial(2*n, n))/2: n in [ 0..20]]; // Vincenzo Librandi, Nov 24 2012 CROSSREFS Cf. A069723, A069720. Sequence in context: A026294 A199688 A275998 * A011544 A127503 A214363 Adjacent sequences:  A098398 A098399 A098400 * A098402 A098403 A098404 KEYWORD easy,nonn AUTHOR Paul Barry, Sep 06 2004 STATUS approved

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Last modified July 28 05:31 EDT 2021. Contains 346317 sequences. (Running on oeis4.)