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 A087081 #5 Oct 20 2020 14:56:12 %S A087081 0,1,6,24,48,156,192,580,836,1444,1660,4596,4980,13184,14768,17308, %T A087081 21756,55888,58768,146416,157552,181008,196304,481664,500096,765648, %U A087081 825152,1073920,1148288,2745728,2768768,6505728,7453952,8233792,8736960,9984832,10208064 %N A087081 Sum of the elements in the coprime subsets of the integers 1 to n. %C A087081 A coprime set of integers has (m,n)=1 for each pair of integers in the set. %D A087081 Alan Sutcliffe, Divisors and Common Factors in Sets of Integers, awaiting publication. %H A087081 Fausto A. C. Cariboni, <a href="/A087081/b087081.txt">Table of n, a(n) for n = 0..120</a> %e A087081 a(4)=48 since the 12 coprime subsets of (1,2,3,4) are ( ) (1) (2) (3) (4) (1,2) (1,3) (1,4) (2,3) (3,4) (1,2,3) (1,3 4) and the sum of the elements is 48. %Y A087081 A087078 gives the sum of the elements in the primitive subsets. A084422 gives the number coprime subsets. A087080 gives the number of elements in coprime subsets. %K A087081 nonn %O A087081 0,3 %A A087081 Alan Sutcliffe (alansut(AT)ntlworld.com), Aug 12 2003 %E A087081 Terms a(35) and beyond from _Fausto A. C. Cariboni_, Oct 20 2020