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Search: id:A114530
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| A114530 |
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a(n) = permanent of a bordered n X n (1,-1)-matrix with the following property: the elements on the border are 1; if we concatenate the rows of the matrix to form a vector v of length n^2, v_i = -1 if i is not a prime. The border of a matrix consists of the first and the last row and the first and the last column. |
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1
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| 6, 0, 8, 144, -80, -384, -2816, -15360, -125184, 5322240, -22966272, 36771840, -887224320, 1488936960, -217760382976, -1484266291200, -45948014198784, 65021593190400, -3267216288645120, -856122753024000, -3180322010587725824
(list; graph; listen)
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OFFSET
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3,1
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LINKS
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Simone Severini, www-users.york.ac.uk/~ss54
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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) for(n=1, 23, a=matrix(n, n, i, j, if(i==1||j==1||i==n||j==n, 1, -1+2*isprime((i-1)*n+j))); print1(permRWNb(a)", ")) - Herman Jamke (hermanjamke(AT)fastmail.fm), May 15 2007
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CROSSREFS
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Sequence in context: A083680 A010491 A085609 this_sequence A085673 A117492 A022901
Adjacent sequences: A114527 A114528 A114529 this_sequence A114531 A114532 A114533
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KEYWORD
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sign
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AUTHOR
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Simone Severini (ss54(AT)york.ac.uk), Feb 15 2006
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EXTENSIONS
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More terms (and corrected definition) from Herman Jamke (hermanjamke(AT)fastmail.fm), May 15 2007
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