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 A343229 #13 Apr 09 2021 11:38:23
%S A343229 0,0,1,0,0,3,2,2,1,0,0,1,0,0,7,6,6,5,4,4,5,4,4,3,2,2,1,0,0,1,0,0,3,2,
%T A343229 2,1,0,0,1,0,0,15,14,14,13,12,12,13,12,12,11,10,10,9,8,8,9,8,8,11,10,
%U A343229 10,9,8,8,9,8,8,7,6,6,5,4,4,5,4,4,3,2,2,1,0
%N A343229 A binary encoding of the digits "-1" in balanced ternary representation of n.
%C A343229 The ones in the binary representation of a(n) correspond to the digits "-1" in the balanced ternary representation of n.
%C A343229 We can extend this sequence to negative indices: a(-n) = A343228(n) for any n >= 0.
%H A343229 Rémy Sigrist, <a href="/A343229/b343229.txt">Table of n, a(n) for n = 0..6561</a>
%H A343229 Wikipedia, <a href="https://en.wikipedia.org/wiki/Balanced_ternary">Balanced ternary</a>
%F A343229 a(n) = A289831(A060373(n)).
%e A343229 The first terms, alongside the balanced ternary representation of n (with "T" instead of digits "-1") and the binary representation of a(n), are:
%e A343229 n a(n) ter(n) bin(a(n))
%e A343229 -- ---- ------ ---------
%e A343229 0 0 0 0
%e A343229 1 0 1 0
%e A343229 2 1 1T 1
%e A343229 3 0 10 0
%e A343229 4 0 11 0
%e A343229 5 3 1TT 11
%e A343229 6 2 1T0 10
%e A343229 7 2 1T1 10
%e A343229 8 1 10T 1
%e A343229 9 0 100 0
%e A343229 10 0 101 0
%e A343229 11 1 11T 1
%e A343229 12 0 110 0
%e A343229 13 0 111 0
%e A343229 14 7 1TTT 111
%e A343229 15 6 1TT0 110
%o A343229 (PARI) a(n) = { my (v=0, b=1, t); while (n, t=centerlift(Mod(n, 3)); if (t==-1, v+=b); n=(n-t)\3; b*=2); v }
%Y A343229 Cf. A059095, A060373, A140267, A289814, A289831, A343228, A343230, A343231, A005836 (indices of 0's).
%K A343229 nonn,look,base
%O A343229 0,6
%A A343229 _Rémy Sigrist_, Apr 08 2021