This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A327390 #6 Sep 16 2019 12:38:09
%S A327390 1,2,2,2,2,3,2,2,3,3,2,3,2,3,3,2,2,4,2,3,4,3,2,3,3,3,4,3,2,4,2,2,3,3,
%T A327390 3,4,2,3,4,3,2,5,2,3,4,3,2,3,3,4,3,3,2,5,3,3,4,3,2,4,2,3,6,2,4,4,2,3,
%U A327390 3,4,2,4,2,3,4,3,3,5,2,3,5,3,2,5,3,3,4
%N A327390 Number of connected divisors of n.
%C A327390 A number n with prime factorization n = prime(m_1)^s_1 * ... * prime(m_k)^s_k is connected if the simple labeled graph with vertex set {m_1,...,m_k} and edges between any two vertices with a common divisor greater than 1 is connected. Connected numbers are listed in A305078. The maximum connected divisor of n is A327076(n).
%H A327390 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 A327390 primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
%t A327390 zsm[s_]:=With[{c=Select[Tuples[Range[Length[s]],2],And[Less@@#,GCD@@s[[#]]]>1&]},If[c=={},s,zsm[Sort[Append[Delete[s,List/@c[[1]]],LCM@@s[[c[[1]]]]]]]]];
%t A327390 Table[Length[Select[Divisors[n],Length[zsm[primeMS[#]]]<=1&]],{n,100}]
%Y A327390 See link for additional cross-references.
%Y A327390 Cf. A000005, A001221, A033273, A286518, A304714, A304716.
%K A327390 nonn
%O A327390 1,2
%A A327390 _Gus Wiseman_, Sep 15 2019