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