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

1,36

Links

Table of n, a(n) for n=1..90.

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}]

Crossrefs

Cf. A030231, A050334, A074206, A308063, A357374.

Sequence in context: A178498 A353422 A095408 * A133008 A102550 A293139

Adjacent sequences: A357372 A357373 A357374 * A357376 A357377 A357378

Keyword

nonn

Author

Ilya Gutkovskiy, Sep 25 2022

Status

approved