It seems like I haven't assigned each result to a - I don't know how to do that. I've tried the syntax suggested above but I get the output I posted earlier.

Ok, it's a fairly big expression.

This is the loop: m:=20;n:=20;for o from 0 to 20 do (factorial(m)*factorial(n)*factorial(o)*(sum(sum(sum(sum(sum(sum(f, p = 0 .. limp), q = 0 .. limq), r = 0 .. limr), s = 0 .. lims), t = 0 .. limt), u = 0 .. limu))^2/2^(m+n+o)) end do;

This gives the following solutions:

                                     m:=20
                                     n:=20
                              4.236591150 10 -13  
                              4.909747644 10 -14  
                              3.395838917 10  -13 
                              1.036096911 10 -14  
                              2.922128774 10  -15 
                              3.341935047 10  -17 
                              3.892692877 10  -19 
                              6.112944026 10   -24
                              8.007547937 10   -23
                              7.975129906 10   -25
                              2.010079762 10   -28
                              6.222118397 10   -29
                              1.904247006 10   -32
                              1.164744077 10   -33
                              1.496493118 10   -37
                              5.479208231 10   -39
                              6.068188919 10   -44
                              2.990477960 10   -45
                              4.367066562 10   -49
                              5.491621180 10   -53
                              7.828868944 10   -57
 

 I then tried:

Total:=0:

m:=20;n:=20;for o from 0 to 20 do (factorial(m)*factorial(n)*factorial(o)*(sum(sum(sum(sum(sum(sum(f, p = 0 .. limp), q = 0 .. limq), r = 0 .. limr), s = 0 .. lims), t = 0 .. limt), u = 0 .. limu))^2/2^(m+n+o));

# generate solution a

Total:=Total + a;

end do;

And I got the following solutions:

                                     m:=20
                                     n:=20
                                1.832301891 10 -31  
                                   Total:=a
                              5.327896550 10   -32
                                     Total:=2 a
                              7.746125753 10   -33
                                     Total:=3 a
                              7.507961596 10   -34
                                     Total:=4 a
                              5.457840084 10   -35
                                     Total:=5 a
                              3.174019247 10   -36
                                     Total:=6 a
                              1.538215065 10   -37
                                     Total:=7 a
                              6.389660361 10   -39
                                     Total:=8 a
                              2.322450905 10   -40
                                     Total:=9 a
                              7.503480992 10   -42
                                    Total:=10 a
                              2.181833178 10   -43
                                    Total:=11 a
                              5.767500099 10   -45
                                    Total:=12 a
                              1.397542805 10   -46
                                    Total:=13 a
                              3.125939160 10   -48
                                    Total:=14 a
                              6.492489257 10   -50
                                    Total:=15 a
                              1.258573941 10   -51
                                    Total:=16 a
                              2.287270387 10   -53
                                    Total:=17 a
                              3.912256678 10   -55
                                    Total:=18 a
                              6.319949233 10   -57
                                    Total:=19 a
                              9.672054683 10   -59
                                    Total:=20 a
                              1.406201324 10   -60
                                    Total:=21 a
 

I hope this is what you need.

I should have been more specific. It isn't a list but twenty solutions. I tried to add them as they are generated as you suggested but I am not having any luck - I've never done a loop before and have only a basic knowledge of Maple.