how to merge two lists without repetitions?

input [x,y,z] [a,b,x]

return [x,y,z,a,b]

how to get the power of monomials

if input x, return 1

if input x*y^2, return [1,2]

http://www.maplesoft.com/applications/view.aspx?SID=5083&view=html&L=F

Error, (in hanoi) cannot determine if this expression is true or false: 0 < n

N:=n:moves:=[];
hanoi:=proc(N,source,dest,aux) global moves;
if N>0 then
hanoi(N-1,source,aux,dest):
moves:=[moves[],[N,source,dest]]:
hanoi(N-1,aux,dest,source);
end if:
end proc:
sol:=hanoi(n,1,3,2);

There is million items in list, 

what is the difference between seq and for loop ?

is seq faster than for loop?

it is very slow when running code below, how to speed up this part of code?

https://gist.github.com/LovelyYanki/c0b61fbb9d5954b34e03#file-gistfile1-txt

HSKeyIn := Table();
for ij from 1 to 1685159 do
s := solve([mm[ij][1,1]=1,mm[ij][1,2]=1,mm[ij][1,3]=1],[a,b,c]):
if nops(s) > 0 then
if (rhs(s[1][1]) = 1 or rhs(s[1][1]) = 0) and (rhs(s[1][2]) = 1 or rhs(s[1][2]) = 0) and (rhs(s[1][3]) = 1 or rhs(s[1][3]) = 0) then
#print(lhs(indices(T3, pairs)[ij])):
#print("***"):
h := HilbertSeries([mm[ij][1,1],mm[ij][1,2],mm[ij][1,3]], {a,b,c}, z):
#print(h):
if not assigned(HSkeyIn[h]) then
if mod(ij, 100) = 0 then
print(ij):
end if:
HSkeyIn[h] := [[mm[ij][1,1],mm[ij][1,2],mm[ij][1,3]]]:
else
if mod(ij, 100) = 0 then
print(ij):
end if:
HSkeyIn[h] := [op(HSkeyIn[h]), [mm[ij][1,1],mm[ij][1,2],mm[ij][1,3]]]:
end if:

end if:
end if:
od:

mm := [[a, 1], [a, b]];
mmseq := {seq(mm[ij],ij=1..2)};

how to filter above in seq when any items in the [] has 1

criteria is below

if mm[ij][1] = 1 or mm[ij][2] = 1 or mm[ij][3] = 1 then
Dummy := 0:
else
mm2 := [op(mm2), mm[ij]]:
end if