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