|
| |
|
|
A204265
|
|
Permanent of n X n matrix M with M(i,j) = (i+j) (mod 3).
|
|
2
|
|
|
|
2, 2, 9, 40, 144, 1032, 7824, 48816, 530712, 5619456, 50015232, 707802624, 9591229440, 112586112000, 1938416832000, 32061464064000, 469224244224000, 9509523337728000, 185772505605120000, 3261008730405888000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Permanent of the n-th principal submatrix of A204263.
|
|
|
LINKS
|
Table of n, a(n) for n=1..20.
|
|
|
MATHEMATICA
|
f[i_, j_] := 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, 14}, {i, 1, n}]] (* A204263 *)
Permanent[m_] :=
With[{a = Array[x, Length[m]]},
Coefficient[Times @@ (m.a), Times @@ a]];
Table[Permanent[m[n]], {n, 1, 22}] (* A204265 *)
|
|
|
PROG
|
(PARI) matperm(M)=my(n=#M, t); sum(i=1, n!, t=numtoperm(n, i); prod(j=1, n, M[j, t[j]])); a(n)=matperm(matrix(n, n, i, j, (i+j)%3)) \\ Ralf Stephan, Oct 19 2013
|
|
|
CROSSREFS
|
Cf. A204263.
Sequence in context: A220971 A308519 A205390 * A081086 A019514 A135816
Adjacent sequences: A204262 A204263 A204264 * A204266 A204267 A204268
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Clark Kimberling, Jan 15 2012
|
|
|
STATUS
|
approved
|
| |
|
|
