A363520 Product of the divisors of n that are < sqrt(n).
1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 6, 1, 2, 3, 2, 1, 6, 1, 8, 3, 2, 1, 24, 1, 2, 3, 8, 1, 30, 1, 8, 3, 2, 5, 24, 1, 2, 3, 40, 1, 36, 1, 8, 15, 2, 1, 144, 1, 10, 3, 8, 1, 36, 5, 56, 3, 2, 1, 720, 1, 2, 21, 8, 5, 36, 1, 8, 3, 70, 1, 1152, 1, 2, 15, 8, 7, 36, 1, 320, 3, 2, 1
Offset: 1
Examples
The product of divisors of 16 that are < sqrt(16) = 4 is 1*2 = 2, so a(16) = 2.
Programs
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Mathematica
a[n_] := Times @@ Select[Divisors[n], #^2 < n &]; Array[a, 100]
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PARI
a(n) = vecprod(select(x->(x^2