OFFSET
1,6
PROG
(PARI) {a(n)=prod(i=0, n, matrix(n+1, n+1, r, c, if(r>=c, if((r+n+1-i)%(c+n+1-i)==0, moebius((r+n+1-i)/(c+n+1-i)), 0))))[n, 2]}
CROSSREFS
KEYWORD
sign
AUTHOR
Wouter Meeussen and Paul D. Hanna, Mar 05 2006
STATUS
approved