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Search: id:A085510
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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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+0
1
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| 0, 1, 2, 16, 150, 2757, 56252, 1843637, 71277004, 3592359440, 197924252436, 14915743198773, 1183551535975484, 123024814715081453, 13742505172992983210, 1747020721154054373156, 240574984100927602314902
(list; graph; listen)
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OFFSET
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1,3
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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); (Deutsch)
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PROGRAM
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(PARI) permRWNb(a)=n=matsize(a)[1]; if(n==1, return(a[1, 1])); sg=1; in=vectorv(n); x=in; x=a[, n]-sum(j=1, n, a[, j])/2; p=prod(i=1, n, x[i]); for(k=1, 2^(n-1)-1, sg=-sg; j=valuation(k, 2)+1; z=1-2*in[j]; in[j]+=z; x+=z*a[, j]; p+=prod(i=1, n, x[i], sg)); return(2*(2*(n%2)-1)*p) ephi(n)=if(n>0, eulerphi(n), 0) for(n=1, 23, a=matrix(n, n, i, j, ephi(abs(i-j))); print1(permRWNb(a)", ")) - Herman Jamke (hermanjamke(AT)fastmail.fm), May 14 2007
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CROSSREFS
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Cf. A071083.
Adjacent sequences: A085507 A085508 A085509 this_sequence A085511 A085512 A085513
Sequence in context: A024915 A103885 A124578 this_sequence A012391 A012387 A009518
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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 19 2003
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 17 2004
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