A387140 a(n) = (1/n) * Product_{k=1..n} radical(k) for n >= 1, a(0) = 1, where radical(n) is the product of distinct prime factors of n, cf. A007947.

1, 1, 1, 2, 3, 12, 60, 360, 630, 1680, 15120, 151200, 831600, 9979200, 129729600, 1816214400, 3405402000, 54486432000, 308756448000, 5557616064000, 52797352608000, 1055947052160000, 22174888095360000, 487847538097920000, 2805123344063040000, 13464592051502592000

Offset

0,4

Links

Table of n, a(n) for n=0..25.

Formula

a(n) = A048803(n) / n for n >= 1.

Maple

a := n -> if n = 0 then 1 else mul(NumberTheory:-Radical(i), i=1..n) / n fi:

Mathematica

A387140[n_] := If[n == 0, 1, Quotient[Times @@ ResourceFunction["IntegerRadical"][Range[1, n]], n]]; Table[A387140[n], {n, 0, 25}]

Crossrefs

Cf. A007947, A048803, A387141.

Sequence in context: A191464 A052183 A123899 * A188588 A032133 A155579

Adjacent sequences: A387137 A387138 A387139 * A387141 A387142 A387143

Keyword

nonn

Author

Peter Luschny, Aug 18 2025

Status

approved