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 A333548 #37 Jan 09 2021 21:04:09
%S A333548 3,11,39,248,844,2752,57071,58056875
%N A333548 Numbers k such that A005132(k-1) = k.
%C A333548 Subtracting 1 from k gives the index of a term A005132(k-1) = k in Recamán's sequence A005132 such that subtracting k would reach 0. This is not permitted, so we must add k instead, obtaining A005132(k) = 2*k.
%C A333548 If A005132(k-1) = k, A005132(k) = 2*k. The converse is not always true. For example, A005132(75) = 228 and A005132(76) = 228 - 76 = 152. - _Seiichi Manyama_, May 02 2020
%H A333548 <a href="/index/Rea#Recaman">Index entries for sequences related to Recamán's sequence</a>
%e A333548 A005132(10)=11, so 11 is a term (and A005132(11)=22).
%o A333548 (Python)
%o A333548 A333548_list, A005132_set, y = [], {0}, 0
%o A333548 for n in range(1,10**10):
%o A333548 y -= n
%o A333548 if y <= 0 or y in A005132_set:
%o A333548 y += 2*n
%o A333548 A005132_set.add(y)
%o A333548 if y == n+1:
%o A333548 A333548_list.append(y) # _Chai Wah Wu_, May 02 2020
%Y A333548 Cf. A005132, A064568, A064569, A187921, A187922, A331659.
%K A333548 nonn,more
%O A333548 1,1
%A A333548 _N. J. A. Sloane_, May 01 2020
%E A333548 a(8) from _Chai Wah Wu_, May 02 2020