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A085905
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Permanent of the symmetric n X n matrix M defined by M(i,j) = lcm(i,j) for 1 <= i,j <= n.
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1
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1, 6, 144, 5952, 772560, 73664640, 29745273600, 8715934402560, 5068085799813120, 2756328707949465600, 4581860819083475558400, 2696083278990328597708800, 7844679216026128507826995200
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(2)=6 since the 2 by 2 matrix A with rows [1,2],[2,2] has permanent 1*2+2*2=6.
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MAPLE
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with(linalg): a:=(i, j)->lcm(i, j): seq(permanent(matrix(n, n, a)), n=1..14); # Emeric Deutsch, Feb 08 2005
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MATHEMATICA
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a[n_] := Permanent[Table[LCM[i, j], {i, 1, n}, {j, 1, n}]]; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 1, 14}] (* Jean-François Alcover, Jan 07 2016 *)
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PROG
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(PARI) a(n)=matpermanent(matrix(n, n, r, c, lcm(r, c)));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 16 2003
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EXTENSIONS
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STATUS
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approved
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