Problem 60 alt attempt

60_alt.hs

@@ -1,11 +1,12 @@
+{-# LANGUAGE BangPatterns #-}
 import Data.List
 
-upper = 10000
+upper = 8000
 
 isPrime :: Int -> Bool
 isPrime x = null [k | k <- [2..x-1], k * k <= x, x `mod` k == 0]
 
-primes = [x | x <- [2..upper], isPrime x]
+!primes = [x | x <- [2..upper], isPrime x]
     
 isPrimeNew :: Int -> Bool
 isPrimeNew x
@@ -17,4 +18,28 @@ isPrimePair a b = isPrime(read(show a ++ show b)) && isPrime(read(show b ++ show
 
 primePairs = [(a, b) | a <- primes, b <- primes, a < b, isPrimePair a b]
 
-main = print primePairs 
+primeSets = [(a, b, c, d, e) | a <- primes,
+                               b <- primes,
+                               a < b,
+                               isPrimePair b a,
+
+                               c <- primes,
+                               b < c,
+                               isPrimePair c a,
+                               isPrimePair c b,
+
+                               d <- primes,
+                               c < d,
+                               isPrimePair d a,
+                               isPrimePair d b,
+                               isPrimePair d c,
+
+                               e <- primes, 
+                               d < e,
+                               isPrimePair e a,
+                               isPrimePair e b,
+                               isPrimePair e c,
+                               isPrimePair e d]
+
+
+main = print $ head primeSets