A280132 Partial products of A029940 (Product_{d|n} phi(d)).

1, 1, 2, 4, 16, 64, 384, 3072, 36864, 589824, 5898240, 188743680, 2264924160, 81537269760, 5218385264640, 333976656936960, 5343626510991360, 769482217582755840, 13850679916489605120, 3545774058621338910720, 510591464441472803143680, 51059146444147280314368000

Offset

1,3

Comments

phi(n) is the number of totatives of n (A000010).

Links

Table of n, a(n) for n=1..22.

Formula

a(n) = Product_{i=1..n} A029940(i).

Mathematica

FoldList[Times[#1, #2] &, Array[Product[EulerPhi@ d, {d, Divisors@ #}] &, 22]] (* Michael De Vlieger, Dec 27 2016 *)

Prog

(Magma) [&*[&*[EulerPhi(d): d in Divisors(k)]: k in [1..n]]: n in [1..100]]

Crossrefs

Cf. A000010, A029940, A280131 (partial sums of A029940), A280133 (partial products of A057661).

Sequence in context: A151371 A001900 A113247 * A138870 A153992 A153995

Adjacent sequences: A280129 A280130 A280131 * A280133 A280134 A280135

Keyword

nonn

Author

Jaroslav Krizek, Dec 27 2016

Status

approved