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.

A318721 Number of strict relatively prime factorizations of n.

This page as a plain text file.
%I A318721 #5 Sep 02 2018 17:08:20
%S A318721 1,0,0,0,0,1,0,0,0,1,0,1,0,1,1,0,0,1,0,1,1,1,0,2,0,1,0,1,0,4,0,0,1,1,
%T A318721 1,2,0,1,1,2,0,4,0,1,1,1,0,2,0,1,1,1,0,2,1,2,1,1,0,6,0,1,1,0,1,4,0,1,
%U A318721 1,4,0,4,0,1,1,1,1,4,0,2,0,1,0,6,1,1,1
%N A318721 Number of strict relatively prime factorizations of n.
%C A318721 a(1) could be either 0 or 1.
%e A318721 The a(60) = 6 factorizations are (3*20), (4*15), (5*12), (2*3*10), (2*5*6), (3*4*5).
%t A318721 strfacs[n_]:=If[n<=1,{{}},Join@@Table[(Prepend[#1,d]&)/@Select[strfacs[n/d],Min@@#1>d&],{d,Rest[Divisors[n]]}]];
%t A318721 Table[Length[Select[strfacs[n],GCD@@#==1&]],{n,50}]
%Y A318721 Cf. A001055, A007716, A045778, A078374, A281116, A317748, A318720.
%K A318721 nonn
%O A318721 1,24
%A A318721 _Gus Wiseman_, Sep 02 2018