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 A187494 #10 Feb 16 2025 08:33:14
%S A187494 1,1,3,3,5,5,9,12,21,27,41,46,74,99,137,153,203,307,414,464,612,788,
%T A187494 1126,1292,1645,2039,2614,3291,4120,5127,6356,7180,9786
%N A187494 Number of 7-element nondividing subsets of {1, 2, ..., n}.
%C A187494 A set is called nondividing if no element divides the sum of any nonempty subset of the other elements.
%H A187494 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/NondividingSet.html">Nondividing Set</a>
%e A187494 a(43) = 1 because there is one 7-element nondividing subset of {1,2,...,43}: {24,28,31,35,36,40,43}.
%Y A187494 Column 7 of triangle A187489. Cf. A068063.
%K A187494 nonn,more
%O A187494 43,3
%A A187494 _Alois P. Heinz_, Mar 10 2011