enum & search 500 X 500

gistfile1.hs

Prelude Data.List> length [(x, y*y) | y <-[1..31], a<-[1..499],
     b<-[a..div 500 a-1], let x=a*b,  5<x, x<500, mod y x == 0]
85
(0.41 secs, 16891796 bytes)

Prelude Data.List> length [(x, y*y) | y <-[1..31], a<-[1..499],
     b<-[a..div 500 a-1], let x=a*b,  5<x, mod y x == 0]
85
(0.37 secs, 15572324 bytes)

-- http://news.gmane.org/find-root.php?message_id=%3cEAC01DCF%2d1443%2d4FC2%2d9904%2d4F938FAC7C81%40cs.otago.ac.nz%3e
-- http://stackoverflow.com/questions/16552650/haskell-list-comprehension-cant-enumerate-n-n#comment23802769_16552650
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