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A204438
Permanent of the n-th principal submatrix of A204437.
4
1, 0, 1, 2, 4, 20, 80, 288, 2016, 12096, 67392, 597888, 4783104, 35942400, 389145600, 3891456000, 36910080000, 472283136000, 5667397632000, 64963067904000, 959814696960000, 13437405757440000, 180681897811968000, 3028176742219776000, 48450827875516416000
OFFSET
0,4
COMMENTS
Also the number of permutations pi in S_n such that pi(i) + i != 2 (mod 3) for all i. - Peter Kagey, Jan 25 2021
MATHEMATICA
f[i_, j_] := Mod[(1 + i + j)^2, 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, 14}, {i, 1, n}]] (* A204437 *)
Join[{1}, Table[Permanent[m[n]], {n, 1, 22}]] (* A204438 *)
CROSSREFS
Sequence in context: A204550 A009291 A081440 * A325791 A188326 A158094
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 15 2012
EXTENSIONS
Typo in name corrected by Michel Marcus, Nov 11 2016
a(0) and a(23)-a(24) from Pontus von Brömssen, Jan 29 2021
STATUS
approved