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%I #28 Jan 19 2021 14:35:37
%S 0,2,2,1,1,1,6,0,0,6,8,8,2,8,8,7,7,7,7,7,7,3,6,6,3,6,6,3,5,5,8,5,5,8,
%T 5,5,4,4,4,4,4,4,4,4,4,18,3,3,0,3,3,0,3,3,18,20,20,5,2,2,5,2,2,5,20,
%U 20,19,19,19,1,1,1,1,1,1,19,19,19,24,18,18,24,0,0,6,0,0,24,18,18,24
%N The sum of the i-th ternary digits of n, k, and A(n,k) equals 0 (mod 3) for each i>=0 (leading zeros included); square array A(n,k), n>=0, k>=0, read by antidiagonals.
%H Alois P. Heinz, <a href="/A253586/b253586.txt">Antidiagonals n = 0..200, flattened</a>
%H Rémy Sigrist, <a href="/A253586/a253586.png">Colored representation of the table for 0 <= n, k < 3^7</a> (where the hue is function of T(n, k))
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Set_(game)">Set (game)</a>
%F A(n,k) = A(floor(n/3),floor(k/3))*3+(6-(n mod 3)-(k mod 3) mod 3), A(0,0) = 0.
%e Square array A(n,k) begins:
%e 0, 2, 1, 6, 8, 7, 3, 5, 4, ...
%e 2, 1, 0, 8, 7, 6, 5, 4, 3, ...
%e 1, 0, 2, 7, 6, 8, 4, 3, 5, ...
%e 6, 8, 7, 3, 5, 4, 0, 2, 1, ...
%e 8, 7, 6, 5, 4, 3, 2, 1, 0, ...
%e 7, 6, 8, 4, 3, 5, 1, 0, 2, ...
%e 3, 5, 4, 0, 2, 1, 6, 8, 7, ...
%e 5, 4, 3, 2, 1, 0, 8, 7, 6, ...
%e 4, 3, 5, 1, 0, 2, 7, 6, 8, ...
%p A:= proc(n, k) local i, j; `if`(n=0 and k=0, 0,
%p A(iquo(n, 3, 'i'), iquo(k, 3, 'j'))*3 +irem(6-i-j, 3))
%p end:
%p seq(seq(A(n, d-n), n=0..d), d=0..14);
%Y Column k=0 and row n=0 gives A004488.
%Y Main diagonal gives A001477.
%Y A(n,floor(n/3)) gives A060587.
%Y Cf. A090245, A253587.
%K nonn,base,tabl,look
%O 0,2
%A _Alois P. Heinz_, Jan 04 2015
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