A357375 Number of ordered factorizations of n into numbers > 1 with an even number of distinct prime divisors.
1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 2, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 2, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 3, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 2, 1, 1, 1, 1, 0, 2
Offset: 1
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
f[n_] := Boole[EvenQ[PrimeNu[n]]]; a[1] = 1; a[n_] := a[n] = Sum[If[d < n, f[n/d] a[d], 0], {d, Divisors[n]}]; Table[a[n], {n, 1, 90}]