A086094 - OEIS

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A086094

Permanent of the n X n matrix whose element (i,j) equals t(|i-j|) where t(n) is the number of divisors of n and t(0) = 0.

0, 1, 4, 49, 594, 9088, 192550, 4400305, 123753812, 3913346101, 143259991494, 5423531436645, 254447352721880, 12256517669340701, 645137240849841756, 37228477466802215873, 2388339009798778979334, 155663410717277848640228

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Table of n, a(n) for n=1..18.

PROG

(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) ndiv(n)=if(n>0, numdiv(n), 0) for(n=1, 23, a=matrix(n, n, i, j, ndiv(abs(i-j))); print1(permRWNb(a)", ")) - Herman Jamke (hermanjamke(AT)fastmail.fm), May 14 2007

CROSSREFS

Cf. A071084.

Sequence in context: A273230 A199028 A189146 * A055793 A202829 A204233

Adjacent sequences: A086091 A086092 A086093 * A086095 A086096 A086097

KEYWORD

nonn

AUTHOR

Yuval Dekel (dekelyuval(AT)hotmail.com), Aug 24 2003

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), May 14 2007

STATUS

approved