A204258 Permanent of the n-th principal submatrix of A204257.

1, 1, 7, 54, 346, 3732, 50928, 636288, 10421856, 204446592, 3783985632, 84204904320, 2154137877504, 52813565568000, 1488803964595200, 46983956781312000, 1434084567201792000, 48976637440702464000, 1838658764187353088000, 67159997418955456512000

Offset: 0

Author

Clark Kimberling, Jan 14 2012

Keywords

• nonn

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 0..35

Crossrefs

Cf. A204257.

Programs

Mathematica

f[i_, j_] := 1 + Mod[i + 2 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}]]  (* A204257 *)
Join[{1},Table[Permanent[m[n]], {n, 1, 20}]]  (* A204258 *)

PARI

a(n) = matpermanent(matrix(n, n, i, j, 1 + ((i+2*j) % 3))); \\ Michel Marcus, Jan 30 2021

Extensions

a(0) and a(19) from Pontus von Brömssen, Jan 30 2021