A204430 - OEIS

%I #6 Jul 12 2012 00:39:59

%S 1,2,9,34,144,1032,6936,48816,530712,5005152,50015232,707802624,

%T 8714718720,112586112000,1938416832000,29588291712000,469224244224000,

%U 9509523337728000,173318541516288000,3261008730405888000

%N Permanent of the n-th principal submatrix of A204429.

%t f[i_, j_] := Mod[2 i + 2 j, 3];  (* symmetric *)

%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}]]        (* A204429 *)

%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}]   (* A204430 *)

%Y Cf. A204229, A204263.

%K nonn

%O 1,2

%A _Clark Kimberling_, Jan 15 2012