A281027 Partial products of A066570.

1, 2, 6, 48, 240, 34560, 241920, 92897280, 15049359360, 288947699712000, 3178424696832000, 3954468870810501120000, 51408095320536514560000, 232150733172291613910630400000, 338475768965201173081699123200000000, 3493719809197289292455451813740544000000000

Offset: 1

Author

Jaroslav Krizek, Jan 19 2017

Keywords

• nonn

Crossrefs

Cf. A066570(n) = the product of cototatives of n.

Cf. A000178, A280821, A281025.

Programs

Magma

[1] cat [&*[&*[h: h in [2..k] | GCD(h,k) ne 1]: k in [2..n]]: n in [2..100]];

Mathematica

FoldList[Times, Table[Times @@ Select[Range[2, n], ! CoprimeQ[n, #] &], {n, 1, 16}]] (* Amiram Eldar, Aug 16 2025 *)

Formula

a(n) = Product_{i=1..n} A066570(i).

a(n) = A000178(n)/A280821(n). - Amiram Eldar, Aug 16 2025