%I #6 Mar 30 2012 18:58:08
%S 0,1,2,2,0,1,0,1,2,0,1,2,0,1,2,2,0,1,2,0,1,0,1,2,0,1,2,0,1,2,0,1,2,0,
%T 1,2,2,0,1,2,0,1,2,0,1,0,1,2,0,1,2,0,1,2,0,1,2,0,1,2,0,1,2,0,1,2,2,0,
%U 1,2,0,1,2,0,1,2,0,1,0,1,2,0,1,2,0,1,2,0,1,2,0,1,2,0,1,2,0,1,2
%N Infinite matrix: f(i,j)=(2i+j mod 3), by antidiagonals.
%C An infinite block matrix over {0,1,2}. See A204263 for a guide to related matrices and permanents.
%e Northwest corner:
%e 0 1 2 0 1 2
%e 2 0 1 2 0 1
%e 1 2 0 1 2 0
%e 0 1 2 0 1 2
%e 2 0 1 2 0 1
%e 1 2 0 1 2 0
%t f[i_, j_] := Mod[2 i + j, 3];
%t m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}]
%t TableForm[m[8]] (* 8x8 principal submatrix *)
%t Flatten[Table[f[i, n + 1 - i],
%t {n, 1, 14}, {i, 1, n}]] (* A204423 *)
%t Permanent[m_] :=
%t With[{a = Array[x, Length[m]]},
%t Coefficient[Times @@ (m.a), Times @@ a]];
%t Table[Permanent[m[n]], {n, 1, 22}] (* A204424 *)
%Y Cf. A204424, A204263.
%K nonn,tabl
%O 1,3
%A _Clark Kimberling_, Jan 15 2012
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