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Permanent of the n-th principal submatrix of A204549.
3

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

%S 0,1,1,2,4,20,72,288,864,6624,35424,212544,1088640,10056960,75064320,

%T 600514560,4147200000,46664294400,440681472000,4406814720000,

%U 39103948800000,515545067520000

%N Permanent of the n-th principal submatrix of A204549.

%t f[i_, j_] :=

%t Floor[(i + j + 5)/4] - Floor[(i + j + 3)/4];

%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}]] (* A204549 *)

%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}] (* A204550 *)

%Y Cf. A204549, A204269.

%K nonn

%O 1,4

%A _Clark Kimberling_, Jan 16 2012