A204252 Permanent of the n-th principal submatrix of A201208 (in square format).

1, 5, 18, 132, 876, 8820, 85392, 1106496, 14057280, 223560000, 3513456000, 66305952000, 1241430624000, 27127003680000, 589395356928000, 14638710417408000, 362021985626112000, 10073602372700160000, 279369787588448256000

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Mathematica

f[i_, j_] := 1 + Mod[i + j, 2];
m[n_] := Table[f[i, j], {i, 1, n}, {j, 1, n}]
TableForm[m[8]] (* 8x8 principal submatrix *)
Flatten[Table[f[i, n + 1 - i],
  {n, 1, 12}, {i, 1, n}]] (* A201208 in square format *)
Permanent[m_] :=
  With[{a = Array[x, Length[m]]},
   Coefficient[Times @@ (m.a), Times @@ a]];
Table[Permanent[m[n]], {n, 1, 20}]    (* A204252 *)

Crossrefs

Cf. A201208.

Sequence in context: A009365 A140296 A278172 * A281564 A291356 A091059

Adjacent sequences: A204249 A204250 A204251 * A204253 A204254 A204255

Keyword

nonn

Author

Clark Kimberling, Jan 14 2012

Status

approved