%I #7 Sep 18 2019 04:57:34
%S 0,1,0,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,1,1,
%T 1,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,0,1,
%U 1,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0
%N Indicator function for numbers whose prime indices are relatively prime (A289509).
%C First differs from A327515 at index 225.
%C A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. After 2, the first connected number (A305078) with relatively prime prime indices is 195.
%H Gus Wiseman, <a href="https://docs.google.com/document/d/e/2PACX-1vSX9dPMGJhxB8rOknCGvOs6PiyhupdWNpqLsnphdgU6MEVqFBnWugAXidDhwHeKqZe_YnUqYeGOXsOk/pub">Sequences counting and encoding certain classes of multisets</a>
%t Table[Boole[GCD@@PrimePi/@First/@FactorInteger[n]==1],{n,100}]
%Y See link for additional cross-references.
%Y Positions of 0's are A318978.
%Y Positions of 1's are A289509.
%Y Cf. A112798, A281116, A289509, A318721.
%K nonn
%O 1
%A _Gus Wiseman_, Sep 17 2019