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 A072976 a(n) = 2^n*binomial(3*n,n)*(3*n+2). 1
 2, 30, 480, 7392, 110880, 1633632, 23761920, 342328320, 4895294976, 69589977600, 984515051520, 13872712089600, 194821130649600, 2728095278727168, 38106727702855680, 531128942672216064 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..100 FORMULA Sum_{k>=0} 1/a(k) = (7*Pi - 24*log(2))/10 = 0.53556162416898... MATHEMATICA Table[2^n Binomial[3n, n](3n+2), {n, 0, 20}] (* Harvey P. Dale, Aug 20 2011 *) PROG (PARI) a(n)=2^n*binomial(3*n, n)*(3*n+2) (Magma) [2^n*Binomial(3*n, n)*(3*n+2): n in [0..20]]; // Vincenzo Librandi, Aug 20 2011 CROSSREFS Sequence in context: A219706 A318477 A219869 * A143414 A099046 A020547 Adjacent sequences: A072973 A072974 A072975 * A072977 A072978 A072979 KEYWORD easy,nonn AUTHOR Benoit Cloitre, Aug 13 2002 EXTENSIONS a(1) corrected by Harvey P. Dale, Aug 20 2011 STATUS approved

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Last modified May 30 03:43 EDT 2023. Contains 363044 sequences. (Running on oeis4.)