This has solutions in corresponding to solutions which are integral in
and
of ,
(14, 21), (7189, 10981), (165026, 252081), (86968201, 132846121), ... (OEIS A048913
and A048914), giving the nonagonal pentagonal
numbers 1, 651, 180868051, 95317119801, 26472137730696901, ... (OEIS A048915).