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 A204434 #10 May 05 2022 12:29:28
%S A204434 0,4,9,16,192,1032,5184,62496,530712,4188672,61710336,707802624,
%T A204434 7614259200,133983590400,1938416832000,26579819520000,544216485888000,
%U A204434 9509523337728000,158654296829952000,3711395156281344000
%N A204434 Permanent of the n-th principal submatrix of A204433.
%t A204434 f[i_, j_] := Mod[2 i + 2 j + 2, 3];
%t A204434 m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}]
%t A204434 TableForm[m[8]] (* 8x8 principal submatrix *)
%t A204434 Flatten[Table[f[i, n + 1 - i],
%t A204434 {n, 1, 14}, {i, 1, n}]] (* A204433 *)
%t A204434 Permanent[m_] :=
%t A204434 With[{a = Array[x, Length[m]]},
%t A204434 Coefficient[Times @@ (m.a), Times @@ a]];
%t A204434 Table[Permanent[m[n]], {n, 1, 22}] (* A204434 *)
%Y A204434 Cf. A204233, A204263, A204433.
%K A204434 nonn
%O A204434 1,2
%A A204434 _Clark Kimberling_, Jan 15 2012
%E A204434 Typo in definition corrected by _Georg Fischer_, May 05 2022