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%I #20 May 29 2020 02:21:45
%S 1,2,4,8,24,48,96,384,768,1536,6144,12288,36864,147456,294912,589824,
%T 2359296,9437184,18874368,75497472,150994944,301989888,1811939328,
%U 3623878656,10871635968,43486543872,86973087744,347892350976,1391569403904,2783138807808,5566277615616,33397665693696,133590662774784
%N a(n) = Product_{k=1..n} d(2*k - 1), where d() is the number of divisors function A000005.
%e a(3) = d(1)*d(3)*d(5) = 1*2*2 = 4.
%t Rest @ FoldList[Times, 1, DivisorSigma[0, Range[1, 50, 2]]] (* _Amiram Eldar_, May 10 2020 *)
%o (PARI) a(n) = prod(k=1, n, numdiv(2*k-1)); \\ _Michel Marcus_, May 10 2020
%Y Cf. A000005, A066843, A099774.
%K nonn
%O 1,2
%A _Ctibor O. Zizka_, May 10 2020
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