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 A343316 #12 Apr 12 2021 01:36:47
%S A343316 0,0,0,0,1,0,0,-1,-1,0,0,0,4,0,0,0,1,3,3,1,0,0,-1,2,3,2,-1,0,0,0,-2,3,
%T A343316 3,-2,0,0,0,1,-3,-3,4,-3,-3,1,0,0,-1,-4,-3,-4,-4,-3,-4,-1,0,0,0,1,-3,
%U A343316 -3,13,-3,-3,1,0,0,0,1,0,0,-2,12,12,-2,0,0,1,0
%N A343316 Array T(n, k), n, k > 0, read by antidiagonals; the balanced ternary representation of T(n, k) is obtained by multiplying componentwise the digits in the balanced ternary representations of n and of k.
%C A343316 For any k >= 0, n -> T(n, k) is 3^A134021(k)-periodic.
%C A343316 The zeros of the table form a Vicsek fractal (see illustration in Links section).
%H A343316 Rémy Sigrist, <a href="/A343316/b343316.txt">Table of n, a(n) for n = 0..10010</a>
%H A343316 Rémy Sigrist, <a href="/A343316/a343316.png">Colored representation of the table for n, k < 3^6</a> (where the color denotes the sign of T(n, k): red for positive values, blue for negative values, white for zeros)
%H A343316 Wikipedia, <a href="https://en.wikipedia.org/wiki/Vicsek_fractal">Viczek fractal</a>
%F A343316 T(n, k) = T(k, n).
%F A343316 T(m, T(n, k)) = T(T(m, n), k).
%F A343316 T(n, 0) = 0.
%F A343316 T(n, 1) = A102283(n).
%F A343316 T(n, n) = A060374(n).
%e A343316 Array T(n, k) begins:
%e A343316 n\k| 0 1 2 3 4 5 6 7 8 9 10 11 12
%e A343316 ---+--------------------------------------------------
%e A343316 0| 0 0 0 0 0 0 0 0 0 0 0 0 0
%e A343316 1| 0 1 -1 0 1 -1 0 1 -1 0 1 -1 0
%e A343316 2| 0 -1 4 3 2 -2 -3 -4 1 0 -1 4 3
%e A343316 3| 0 0 3 3 3 -3 -3 -3 0 0 0 3 3
%e A343316 4| 0 1 2 3 4 -4 -3 -2 -1 0 1 2 3
%e A343316 5| 0 -1 -2 -3 -4 13 12 11 10 9 8 7 6
%e A343316 6| 0 0 -3 -3 -3 12 12 12 9 9 9 6 6
%e A343316 7| 0 1 -4 -3 -2 11 12 13 8 9 10 5 6
%e A343316 8| 0 -1 1 0 -1 10 9 8 10 9 8 10 9
%e A343316 9| 0 0 0 0 0 9 9 9 9 9 9 9 9
%e A343316 10| 0 1 -1 0 1 8 9 10 8 9 10 8 9
%e A343316 11| 0 -1 4 3 2 7 6 5 10 9 8 13 12
%e A343316 12| 0 0 3 3 3 6 6 6 9 9 9 12 12
%e A343316 Array T(n, k) begins in balanced ternary notation (with "T" instead of digits "-1"):
%e A343316 n\k| 0 1 1T 10 11 1TT 1T0 1T1 10T 100 101 11T 110
%e A343316 ---+----------------------------------------------------------
%e A343316 0| 0 0 0 0 0 0 0 0 0 0 0 0 0
%e A343316 1| 0 1 T 0 1 T 0 1 T 0 1 T 0
%e A343316 1T| 0 T 11 10 1T T1 T0 TT 1 0 T 11 10
%e A343316 10| 0 0 10 10 10 T0 T0 T0 0 0 0 10 10
%e A343316 11| 0 1 1T 10 11 TT T0 T1 T 0 1 1T 10
%e A343316 1TT| 0 T T1 T0 TT 111 110 11T 101 100 10T 1T1 1T0
%e A343316 1T0| 0 0 T0 T0 T0 110 110 110 100 100 100 1T0 1T0
%e A343316 1T1| 0 1 TT T0 T1 11T 110 111 10T 100 101 1TT 1T0
%e A343316 10T| 0 T 1 0 T 101 100 10T 101 100 10T 101 100
%e A343316 100| 0 0 0 0 0 100 100 100 100 100 100 100 100
%e A343316 101| 0 1 T 0 1 10T 100 101 10T 100 101 10T 100
%e A343316 11T| 0 T 11 10 1T 1T1 1T0 1TT 101 100 10T 111 110
%e A343316 110| 0 0 10 10 10 1T0 1T0 1T0 100 100 100 110 110
%o A343316 (PARI) T(n,k) = { if (n==0 || k==0, return (0), my (d=centerlift(Mod(n,3)), t=centerlift(Mod(k,3))); d*t + 3*T((n-d)\3, (k-t)\3)) }
%Y A343316 Cf. A059095, A060374, A102283, A134021, A343317.
%K A343316 sign,tabl,base
%O A343316 0,13
%A A343316 _Rémy Sigrist_, Apr 11 2021