%I A007875
%S A007875 1,1,1,1,1,2,1,1,1,2,1,2,1,2,2,1,1,2,1,2,2,2,1,2,1,2,1,2,1,4,
%T A007875 1,1,2,2,2,2,1,2,2,2,1,4,1,2,2,2,1,2,1,2,2,2,1,2,2,2,2,2,1,4,
%U A007875 1,2,2,1,2,4,1,2,2,4,1,2,1,2,2,2,2,4,1,2,1,2,1,4,2,2,2,2,1,4
%N A007875 Number of ways of writing n as pq, with p<=q, (p,q)=1.
%H A007875 T. D. Noe, <a href="b007875.txt">Table of n, a(n) for n=1..1000</a>
%F A007875 a(n)= (1/2) *Sum_{ d divides n } abs(mu(d))=2^(A001221(n)-1)=A034444(n)/
               2, n > 1. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 25 2002
%Y A007875 Sequence in context: A001221 A064372 A096825 this_sequence A050320 A121382 
               A051265
%Y A007875 Adjacent sequences: A007872 A007873 A007874 this_sequence A007876 A007877 
               A007878
%K A007875 nonn,nice,easy
%O A007875 1,6
%A A007875 Victor Ufnarovski