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 A232054 #7 Dec 11 2019 10:26:51
%S A232054 2,4,7,8,12,15,16,17,22,25,26,29,31,32,35,37,39,45,48,49,52,54,56,57,
%T A232054 61,63,64,66,67,72,75,77,78,81,86,87,90,94,98,99,100,104,107,108,110,
%U A232054 112,115,116,117,120,124,126,127,128,130,135,137,138,140,144
%N A232054 Complement of A056875.
%H A232054 Reinhard Zumkeller, <a href="/A232054/b232054.txt">Table of n, a(n) for n = 1..10000</a>
%t A232054 nmax = 200; S = Range[nmax]; S0 = {}; i = 1;
%t A232054 While[S != S0, ii = NestWhileList[#+S[[#]]&, i+S[[i]], # <= Length[S]&]; S0 = S; S = Delete[S, List /@ Select[ii, # <= Length[S]&]]; i++];
%t A232054 Complement[Range[nmax], S] (* _Jean-François Alcover_, Dec 11 2019 *)
%o A232054 (Haskell)
%o A232054 a232054 n = a232054_list !! (n-1)
%o A232054 a232054_list = c [1..] a056875_list where
%o A232054 c (u:us) vs'@(v:vs) = if u == v then c us vs else u : c us vs'
%K A232054 nonn
%O A232054 1,1
%A A232054 _Reinhard Zumkeller_, Nov 17 2013