gistfile1.hs

-- http://projecteuler.net/index.php?section=problems&id=4

intToPalindrome :: (Num a, Read a) => a -> a
intToPalindrome x = x * 1000 + ( read . reverse . show) x

palindromes = [intToPalindrome n | n <- [999,998..100] ]

is3by3 n = or $ map (\m -> and [n `mod` m == 0, is3 $ n `div` m]) [100 .. 999]
           where is3 l = and [l >= 100, l < 1000]

answer = head $ filter is3by3 palindromes