A334764 a(n) = Product_{k=1..n} d(2*k - 1), where d() is the number of divisors function A000005.

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

Author

Ctibor O. Zizka, May 10 2020

Keywords

• nonn

Examples

			a(3) = d(1)*d(3)*d(5) = 1*2*2 = 4.
		

Crossrefs

Cf. A000005, A066843, A099774.

Programs

Mathematica

Rest @ FoldList[Times, 1, DivisorSigma[0, Range[1, 50, 2]]] (* Amiram Eldar, May 10 2020 *)

PARI

a(n) = prod(k=1, n, numdiv(2*k-1)); \\ Michel Marcus, May 10 2020