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 A138670 #9 Jul 19 2022 08:12:06
%S A138670 0,1,3,4,6,9,10,12,13,15,18,19,21,24,27,28,30,31,33,36,37,39,40,42,45,
%T A138670 46,48,51,54,55,57,58,60,63,64,66,69,72,73,75,78,81,82,84,85,87,90,91,
%U A138670 93,94,96,99,100,102,105,108,109,111,112,114,117,118,120,121
%N A138670 Indices of 0's in Stewart's choral sequence.
%C A138670 Conjecture: essentially partial sums of A106036 (verified for n <= 10000). - _Sean A. Irvine_, Jul 19 2022
%H A138670 Sean A. Irvine, <a href="/A138670/b138670.txt">Table of n, a(n) for n = 0..9999</a>
%F A138670 The set {k*3^(m+1) + (3^m-1)/2 with k >= 0 and m >= 1}.
%Y A138670 Cf. A106036, A116178, A138671.
%K A138670 easy,nonn
%O A138670 0,3
%A A138670 Joel Reyes Noche (joel.noche(AT)up.edu.ph), Mar 26 2008
%E A138670 More terms from _Sean A. Irvine_, Jul 19 2022