OFFSET
1,1
EXAMPLE
For n=2 we have 10 solutions (r,u,s,t), s>=t: (3,6,12,12), (3,6,15,10), (3,6,18,9), (3,6,24,8), (3,6,42,7), (4,4,8,8), (4,4,12,6), (4,4,20,5), (6,3,6,6), (6,3,12,4).
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Aug 10 2001
STATUS
approved