cp's OEIS Frontend

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.

A327521 Number of factorizations of the n-th squarefree number A005117(n) into squarefree numbers > 1.

This page as a plain text file.
%I A327521 #5 Sep 16 2019 12:39:13
%S A327521 1,1,1,1,2,1,2,1,1,2,2,1,1,2,2,1,2,1,5,1,2,2,2,1,2,2,1,5,1,2,1,2,1,2,
%T A327521 2,2,1,1,2,2,5,1,2,5,1,1,2,2,5,1,2,1,2,2,2,1,2,2,2,2,1,1,5,1,5,2,1,1,
%U A327521 5,2,1,5,2,2,2,2,2,1,2,5,1,2,2,1,5,1,2
%N A327521 Number of factorizations of the n-th squarefree number A005117(n) into squarefree numbers > 1.
%H A327521 Gus Wiseman, <a href="https://docs.google.com/document/d/e/2PACX-1vSX9dPMGJhxB8rOknCGvOs6PiyhupdWNpqLsnphdgU6MEVqFBnWugAXidDhwHeKqZe_YnUqYeGOXsOk/pub">Sequences counting and encoding certain classes of multisets</a>
%F A327521 a(n) = A050320(A005117(n)) = A000110(A072047(n)) = A000110(A001222(A005117(n))).
%t A327521 nn=100;
%t A327521 facsusing[s_,n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[facsusing[Select[s,Divisible[n/d,#]&],n/d],Min@@#>=d&]],{d,Select[s,Divisible[n,#]&]}]];
%t A327521 y=Select[Range[nn],SquareFreeQ];
%t A327521 Table[Length[facsusing[Rest[y],n]],{n,y}]
%Y A327521 See link for additional cross-references.
%Y A327521 Cf. A000110, A005117, A007947, A034444, A050320, A072047, A259936.
%K A327521 nonn
%O A327521 1,5
%A A327521 _Gus Wiseman_, Sep 15 2019