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A334764
a(n) = Product_{k=1..n} d(2*k - 1), where d() is the number of divisors function A000005.
0
1, 2, 4, 8, 24, 48, 96, 384, 768, 1536, 6144, 12288, 36864, 147456, 294912, 589824, 2359296, 9437184, 18874368, 75497472, 150994944, 301989888, 1811939328, 3623878656, 10871635968, 43486543872, 86973087744, 347892350976, 1391569403904, 2783138807808, 5566277615616, 33397665693696, 133590662774784
OFFSET
1,2
EXAMPLE
a(3) = d(1)*d(3)*d(5) = 1*2*2 = 4.
MATHEMATICA
Rest @ FoldList[Times, 1, DivisorSigma[0, Range[1, 50, 2]]] (* Amiram Eldar, May 10 2020 *)
PROG
(PARI) a(n) = prod(k=1, n, numdiv(2*k-1)); \\ Michel Marcus, May 10 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Ctibor O. Zizka, May 10 2020
STATUS
approved