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 A204233 #7 Jul 12 2012 00:39:59
%S A204233 0,1,4,49,792,18953,610796,25648641,1359184384,88722005809,
%T A204233 6994262098260,655126226755025,71915748374032232,9144536677714434105,
%U A204233 1333394182537641307324,221002933797466121742433
%N A204233 Permanent of the n-th principal submatrix of A204016.
%t A204233 f[i_, j_] := Max[Mod[i, j], Mod[j, i]];
%t A204233 m[n_] := Table[f[i, j],
%t A204233 {i, 1, n}, {j, 1, n}] (* A204016 *)
%t A204233 Permanent[m_] :=
%t A204233 With[{a = Array[x, Length[m]]},
%t A204233 Coefficient[Times @@ (m.a), Times @@ a]];
%t A204233 Table[Permanent[m[n]], {n, 1, 16}] (* A204233 *)
%Y A204233 Cf. A204016.
%K A204233 nonn
%O A204233 1,3
%A A204233 _Clark Kimberling_, Jan 13 2012