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A204265
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Permanent of n X n matrix M with M(i,j) = (i+j) (mod 3).
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2
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2, 2, 9, 40, 144, 1032, 7824, 48816, 530712, 5619456, 50015232, 707802624, 9591229440, 112586112000, 1938416832000, 32061464064000, 469224244224000, 9509523337728000, 185772505605120000, 3261008730405888000
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OFFSET
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1,1
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COMMENTS
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Permanent of the n-th principal submatrix of A204263.
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LINKS
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Table of n, a(n) for n=1..20.
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MATHEMATICA
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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 *)
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PROG
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(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
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CROSSREFS
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Cf. A204263.
Sequence in context: A220971 A308519 A205390 * A081086 A019514 A135816
Adjacent sequences: A204262 A204263 A204264 * A204266 A204267 A204268
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KEYWORD
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nonn
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AUTHOR
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Clark Kimberling, Jan 15 2012
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STATUS
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approved
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