A382486 Product of distinct prime divisors of n that are <= sqrt(n).

1, 1, 1, 2, 1, 2, 1, 2, 3, 2, 1, 6, 1, 2, 3, 2, 1, 6, 1, 2, 3, 2, 1, 6, 5, 2, 3, 2, 1, 30, 1, 2, 3, 2, 5, 6, 1, 2, 3, 10, 1, 6, 1, 2, 15, 2, 1, 6, 7, 10, 3, 2, 1, 6, 5, 14, 3, 2, 1, 30, 1, 2, 21, 2, 5, 6, 1, 2, 3, 70, 1, 6, 1, 2, 15, 2, 7, 6, 1, 10, 3, 2, 1, 42, 5

Offset: 1

Author

Ilya Gutkovskiy, Apr 10 2025

Keywords

• nonn

Crossrefs

Cf. A007947, A007955, A072499, A097974.

Programs

Mathematica

Table[Times @@ Select[Divisors[n], PrimeQ[#] && # <= Sqrt[n] &], {n, 1, 85}]

PARI

a(n) = vecprod(select(x->x<=sqrt(n), factor(n)[,1])); \\ Michel Marcus, Apr 17 2025

Formula

a(p) = 1, for prime p.