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 A087078 #10 Feb 16 2025 08:32:50 %S A087078 0,1,3,11,22,73,115,341,545,1141,1864,4849,6505,16285,26245,47093, %T A087078 68981,163937,221957,517937,726737,1312865,2093745,4753105,5953777, %U A087078 12335601,19516365,34112821,48603289,107522689,137759953,302797921,422868865 %N A087078 Sum of the elements in the primitive subsets of the integers 1 to n. %C A087078 A primitive set has no element that divides another element in the same set. %D A087078 R. K. Guy, Unsolved Problems in Number Theory, Springer-Verlag, New York, (1994). %H A087078 Fausto A. C. Cariboni, <a href="/A087078/b087078.txt">Table of n, a(n) for n = 0..64</a> %H A087078 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimitiveSequence.html">Primitive Sequence</a>. %e A087078 a(4)=22 since the primitive subsets of (1,2,3,4) are ( ) (1) (2) (3) (4) (2,3) (3,4) and the sum of the elements in these subsets is 22. %Y A087078 A051026 gives the number of primitive subsets. A087077 gives the number of elements in the primitive subsets. A087081 gives the sum of the elements in the coprime subsets. %K A087078 nonn %O A087078 0,3 %A A087078 Alan Sutcliffe (alansut(AT)ntlworld.com), Aug 12 2003