A281024 Partial products of A067392; a(1) = 1.

1, 2, 6, 36, 180, 2700, 18900, 378000, 6804000, 238140000, 2619540000, 141455160000, 1838917080000, 115851776040000, 6951106562400000, 500479672492800000, 8508154432377600000, 995454068588179200000, 18913627303175404800000, 2458771549412802624000000

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Formula

a(1) = 1; for n>1, a(n) = Product_{i=2..n} A067392(i).

Prog

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

Crossrefs

Cf. A067392(n) = sum of cototatives of n.

Cf. A281023.

Sequence in context: A323945 A369080 A101609 * A152668 A213918 A239889

Adjacent sequences: A281021 A281022 A281023 * A281025 A281026 A281027

Keyword

nonn

Author

Jaroslav Krizek, Jan 14 2017

Status

approved