A086065 Permanent of the n X n matrix whose element (i,j) equals sigma(|i-j|) where sigma(n) is the sum of divisors of n and sigma(0) = 0.

0, 1, 6, 196, 5408, 251132, 16873158, 1420208149, 154380762016, 20646224057048, 3433326930682392, 642182473998511032, 152740983098362758624, 40168709084329725908872, 12234598116934739577149272

Offset

1,3

Links

Table of n, a(n) for n=1..15.

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) sgm(n)=if(n>0, sigma(n), 0) for(n=1, 21, a=matrix(n, n, i, j, sgm(abs(i-j))); print1(permRWNb(a)", ")) - Herman Jamke (hermanjamke(AT)fastmail.fm), May 14 2007

Crossrefs

Cf. A085511.

Sequence in context: A283884 A280552 A241137 * A200824 A351888 A340557

Adjacent sequences: A086062 A086063 A086064 * A086066 A086067 A086068

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