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 A088813 #11 Feb 16 2025 08:32:51
%S A088813 1,2,4,7,14,26,43,79,137,246,398,733,1237,2314,3586,6730,11051,21096,
%T A088813 31985,61654,102730,199555,301062,589746,942876,1858881,2793703,
%U A088813 5524251,9193512,18256867,27396918,54517922,88020937,175434632,263194662,525173052
%N A088813 Number of subsets of {1, ..., n} that are double-free or sum-free.
%H A088813 Fausto A. C. Cariboni, <a href="/A088813/b088813.txt">Table of n, a(n) for n = 0..75</a>
%H A088813 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Double-FreeSet.html">Double-Free Set</a>
%H A088813 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Sum-FreeSet.html">Sum-Free Set</a>
%F A088813 a(n) = 2^n - A088812(n) = A050291(n)+A085489(n)-A007865(n).
%K A088813 nonn
%O A088813 0,2
%A A088813 _Reinhard Zumkeller_, Oct 19 2003
%E A088813 Terms a(28) and beyond from _Fausto A. C. Cariboni_, Sep 29 2020