[Haskell-cafe] list comprehension doesn't work

[John]

Hi,

I have to write a function which returns a list of all pairs (x,y) where x,
y ∈ N AND:
–  x is the product of two natural numbers (x = a · b, where a, b ∈ N) AND
–  x is really bigger than 5 but really smaller than 500, AND
–  y is a squer number (y = c² where c ∈ N) NOT greater than 1000, AND
–  x is a divisor of y.

My attempt is as follows:

listPairs :: [(Int, Int)]
listPairs = [(x,y) | x<-[0..], y<-[0..], x<-[0..]*[0..], x > 5, x < 500,
(y*y) < 1001, mod y x == 0]

However it doesn't work unfortunatly 

Could anyone tell me where my mistake is?

Thanks.



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