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%I #12 Feb 02 2014 04:55:52
%S 3,2,16,768,18432,442368,127401984,9172942848,440301256704,
%T 52836150804480,50722704772300800,3652034743605657600,
%U 6135418369257504768000,1030750286035260801024000,98952027459385036898304000,21373637931227167970033664000
%N Denominator of Product{prime(k)^2/(prime(k)^2 - 1) | 0<k<=n}, Numerator: A072044.
%C A072044(n)/a(n) -> (Pi^2)/6 (Leonhard Euler, 1748).
%D M. Sigg: "Pi" p. 191 in Lexikon der Mathematik, Band 4, Spektrum Verlag, 2002.
%e For the first 3 primes: 2,3,5: (2^2/(2^2-1))*(3^2/(3^2-1))*(5^2/(5^2-1)) = (4/3)*(9/8)*(25/24) = (4*9*25)/(3*8*24) = 25/16, therefore a(3)=16;
%e A072044(9)/a(9)=718188003533/440301256704=1.631128671.
%t Rest[Denominator[FoldList[Times,1,(#^2/(#^2-1)&/@Prime[Range[20]])]]] (* _Harvey P. Dale_, Oct 14 2012 *)
%Y Cf. A000040, A001248, A236435, A236436.
%K nonn,frac
%O 1,1
%A _Reinhard Zumkeller_, Jun 09 2002
%E More terms from _Harvey P. Dale_, Oct 14 2012
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