OFFSET
1,36
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
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Sep 25 2022
STATUS
approved