A list comprehension is a special syntax in some programming languages to describe lists. It is similar to the way mathematicians describe sets, with a set comprehension, hence the name.

Some attributes of a list comprehension are:

 They should be distinct from (nested) for loops and the use of map and filter functions within the syntax of the language.
 They should return either a list or an iterator (something that returns successive members of a collection, in order).
 The syntax has parts corresponding to that of set-builder notation. 


Task

Write a list comprehension that builds the list of all Pythagorean triples with elements between   1   and   n.

If the language has multiple ways for expressing such a construct (for example, direct list comprehensions and generators), write one example for each.




var n=20;
[[(x,y,z); [1..n]; {[x..n]}; {[y..n]},{ x*x + y*y == z*z }; _]]
//-->L(L(3,4,5),L(5,12,13),L(6,8,10),L(8,15,17),L(9,12,15),L(12,16,20))