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 A088811 #15 Feb 16 2025 08:32:51
%S A088811 0,0,1,1,4,6,13,19,41,54,110,157,277,394,706,970,1691,2376,3905,5494,
%T A088811 9130,12355,20262,28146,44316,61761,98023,132891,207912,285667,440118,
%U A088811 604322,929737,1252232,1921062,2625852,3933025,5351483,8085728,10856110
%N A088811 Number of subsets of {1, ..., n} that are sum-free but not double-free.
%H A088811 Fausto A. C. Cariboni, <a href="/A088811/b088811.txt">Table of n, a(n) for n = 0..75</a>
%H A088811 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Double-FreeSet.html">Double-Free Set</a>
%H A088811 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Sum-FreeSet.html">Sum-Free Set</a>
%H A088811 Reinhard Zumkeller, <a href="/A088808/a088808.txt">Illustration of initial terms</a>
%F A088811 a(n) = A088808(n) - A088812(n) = A085489(n) - A007865(n).
%K A088811 nonn
%O A088811 0,5
%A A088811 _Reinhard Zumkeller_, Oct 19 2003
%E A088811 Terms a(28) and beyond from _Fausto A. C. Cariboni_, Sep 28 2020