OFFSET
0,4
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..35
Wikipedia, Symmetric matrix
Wikipedia, Toeplitz Matrix
EXAMPLE
For n = 4 the matrix M(4) is
0 1 1 2
1 0 1 1
1 1 0 1
2 1 1 0
with permanent a(4) = 16.
MATHEMATICA
nmax:=20; k[i_]:=Floor[i/2]; a[n_]:=If[n==0, 1, Permanent[ToeplitzMatrix[Array[k, n], Array[k, n]]]]; Table[a[n], {n, 0, nmax}]
PROG
(PARI) tm(n) = {my(m = matrix(n, n, i, j, if (i==1, floor(j/2), if (j==1, floor(i/2))))); for (i=2, n, for (j=2, n, m[i, j] = m[i-1, j-1]; ); ); m; }
a(n) = matpermanent(tm(n));
CROSSREFS
KEYWORD
nonn
AUTHOR
Stefano Spezia, Feb 16 2020
STATUS
approved