%I A057789
%S A057789 0,1,4,6,20,10,56,44,84,60,220,92,364,182,280,344,816,318,1140,520,840,
%T A057789 770,2024,760,2100,1300,2196,1540,4060,1240,4960,2736,3520,2992,4760,
%U A057789 2580,8436,4218,5928,4240,11480,3612,13244,6380,8040,7590,17296,6128
%N A057789 Sum_{k = 1..n, gcd(k,n)=1} k*(n-k).
%C A057789 Equal to convolution sum over positive integers, k, where k<=n and GCD(k,
               n)=1, except in first term, where the convolution sum is 1 instead 
               of 0.
%H A057789 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A057789 Since 1, 3, 5 and 7 are relatively prime to 8 and are <= 8, a(8) = 1*(8-1) 
               +3*(8-3) +5*(8-5) +7*(8-7) = 44.
%Y A057789 Sequence in context: A053892 A013126 A012969 this_sequence A123169 A023863 
               A024480
%Y A057789 Adjacent sequences: A057786 A057787 A057788 this_sequence A057790 A057791 
               A057792
%K A057789 nonn
%O A057789 1,3
%A A057789 Leroy Quet Nov 04 2000