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 A089118 #18 Jun 04 2022 04:31:16
%S A089118 2,8,11,26,29,35,38,80,83,89,92,107,110,116,119,242,245,251,254,269,
%T A089118 272,278,281,323,326,332,335,350,353,359,362,728,731,737,740,755,758,
%U A089118 764,767,809,812,818,821,836,839,845,848,971,974,980,983,998,1001,1007,1010
%N A089118 Nonnegative numbers in (3*A005836 - 1) [A005836 are the numbers with base representation containing no 2].
%C A089118 Numbers k such that the Motzkin number A001006(k) == 2 (mod 3).
%H A089118 Amiram Eldar, <a href="/A089118/b089118.txt">Table of n, a(n) for n = 1..10000</a>
%H A089118 Rob Burns, <a href="https://arxiv.org/abs/1611.04910">Asymptotic density of Motzkin numbers modulo small primes</a>, arXiv:1611.04910 [math.NT], 2016.
%t A089118 (* m = MotzkinNumber *) m[0] = 1; m[n_] := m[n] = m[n - 1] + Sum[ m[k]*m[n - 2 - k], {k, 0, n - 2}]; Select[ Range[1010], Mod[m[#], 3] == 2 &] (* _Jean-François Alcover_, Jul 10 2013 *)
%t A089118 Select[3*Range[350] - 1, DigitCount[# + 1, 3, 2] == 0 &] (* _Amiram Eldar_, Jun 04 2022 *)
%Y A089118 Cf. A005836, A001006, A082575, A089119.
%K A089118 nonn,base
%O A089118 1,1
%A A089118 _Emeric Deutsch_ and _Bruce E. Sagan_, Dec 05 2003
%E A089118 Offset corrected to 1 by _Jean-François Alcover_, Jun 23 2016