A204253 Symmetric matrix given by f(i,j)=1+[(i+j) mod 3].

3, 1, 1, 2, 2, 2, 3, 3, 3, 3, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1

Offset

1,1

Links

Table of n, a(n) for n=1..99.

Example

Northwest corner:
3 1 2 3 1 2 3 1
1 2 3 1 2 3 1 2
2 3 1 2 3 1 2 3
3 1 2 3 1 2 3 1
1 2 3 1 2 3 1 2
2 3 1 2 3 1 2 3

Mathematica

f[i_, j_] := 1 + Mod[i + j, 3];
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}]]  (* A204253  *)
Permanent[m_] :=
  With[{a = Array[x, Length[m]]},
   Coefficient[Times @@ (m.a), Times @@ a]];
Table[Permanent[m[n]], {n, 1, 20}]  (* A204254  *)

Crossrefs

Cf. A204254.

Sequence in context: A175636 A352935 A364757 * A064048 A336218 A016464

Adjacent sequences: A204250 A204251 A204252 * A204254 A204255 A204256

Keyword

nonn,tabl

Author

Clark Kimberling, Jan 14 2012

Status

approved