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A085510
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Permanent of the n X n matrix whose element (i,j) equals phi(|i-j|).
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2
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0, 1, 2, 16, 150, 2757, 56252, 1843637, 71277004, 3592359440, 197924252436, 14915743198773, 1183551535975484, 123024814715081453, 13742505172992983210, 1747020721154054373156, 240574984100927602314902
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OFFSET
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1,3
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LINKS
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EXAMPLE
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a(3)=2 because phi(0)=0, phi(1)=phi(2)=1 and so the matrix is [[0,1,1],[1,0,1],[1,1,0]] with permanent 2.
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MAPLE
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with(numtheory): with(linalg): p:=(i, j)->phi(abs(i-j)): seq(permanent(matrix(n, n, p)), n=1..16); # Emeric Deutsch, Dec 17 2004
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MATHEMATICA
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a[n_] := Permanent[Table[EulerPhi[Abs[i-j]], {i, 1, n}, {j, 1, n}]]; Table[ an = a[n]; Print["a(", n, ") = ", an]; an, {n, 1, 17}] (* Jean-François Alcover, Jan 07 2016 *)
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PROG
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(PARI)
aph(n)={n=abs(n); if(n>0, eulerphi(n), 0); }
a(n)=matpermanent(matrix(n, n, r, c, aph(r-c)));
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CROSSREFS
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KEYWORD
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nonn,hard
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AUTHOR
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Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 19 2003
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EXTENSIONS
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STATUS
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approved
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