A204429 Symmetric matrix: f(i,j)=(2*i + 2*j) mod 3, by antidiagonals.

1, 0, 0, 2, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,4

Comments

A block matrix over {0,1,2}. See A204263 for a guide to related matrices and permanents.

Links

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

Example

Northwest corner:
1 0 2 1 0 2
0 2 1 0 2 1
2 1 0 2 1 0
1 0 2 1 0 2
0 2 1 0 2 1
2 1 0 2 1 0

Mathematica

f[i_, j_] := Mod[2 i + 2 j, 3];  (* symmetric *)
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, 14}, {i, 1, n}]]

Crossrefs

Cf. A204430, A204263.

Sequence in context: A325955 A337311 A004571 * A292560 A086137 A085976

Adjacent sequences: A204426 A204427 A204428 * A204430 A204431 A204432

Keyword

nonn,tabl

Author

Clark Kimberling, Jan 15 2012

Extensions

Definition corrected by Georg Fischer, Oct 25 2021

Status

approved