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 A063017 a(n) = Catalan(n)*(3^(n+1) - 2^(n+1) + 1)/2. 2
 1, 3, 20, 165, 1484, 13986, 135960, 1352637, 13707980, 141061206, 1470489800, 15500280978, 164967244792, 1770548369700, 19143828730800, 208347968093085, 2280730450967820, 25096531231958670, 277445318198433000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Harry J. Smith, Table of n, a(n) for n = 0..200 FORMULA a(n) = Catalan(n)*(3^(n+1) - 2^(n+1) + 1)/2; o.g.f: -(sqrt(1-4x) - sqrt(1-8x)+ sqrt(1-12x) -1)/(4x). MATHEMATICA Table[CatalanNumber[n] (3^(n + 1) - 2^(n + 1) + 1)/2, {n, 0, 20}] (* Wesley Ivan Hurt, Jan 30 2014 *) PROG (PARI) a(n)={binomial(2*n, n)/(n + 1)*(3^(n+1) - 2^(n+1) + 1)/2} \\ Harry J. Smith, Aug 16 2009 CROSSREFS Cf. A000108, A063016. Sequence in context: A258791 A192509 A012882 * A276315 A145329 A051643 Adjacent sequences:  A063014 A063015 A063016 * A063018 A063019 A063020 KEYWORD easy,nonn AUTHOR Olivier Gérard, Jul 04 2001 EXTENSIONS Formula corrected by Harry J. Smith, Aug 16 2009 STATUS approved

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Last modified December 7 00:09 EST 2019. Contains 329812 sequences. (Running on oeis4.)