Calculate the magic number of length = 9 in Haskell

magicnumber.hs

-- Calculate the magic number of length = 9
-- with numbers ranging from 1 to 9, and each number can only occur once
-- and each section of k length is divisable by k

del :: Eq a => [a] -> [a] -> [a]    
del xs ys = [y| y <- ys, not(elem y xs)]

magicNumber :: [Int]
magicNumber = [var8 | 
            x1 <- [1..9],
            x2 <- (del [x1] [2,4..8]),
			let var1 =, mod var1 2 == 0,
			x3 <- (del [x1,x2] [1..9]),
			let var2 = var1 * 10 + x3, mod var2 3 == 0,
			x4 <- (del [x1,x2,x3] [2,4..8]),
			let var3 = var2 * 10 + x4, mod var3 4 == 0,
			x5 <- (del [x1,x2,x3,x4] [5]),
			let var4 = var3 * 10 + x5, mod var4 5 == 0,
			x6 <- (del [x1,x2,x3,x4,x5] [2,4..8]),
			let var5 = var4 * 10 + x6, mod var5 6 == 0,
			x7 <- (del [x1,x2,x3,x4,x5,x6] [1..9]),
			let var6 = var5 * 10 + x7, mod var6 7 == 0,
			x8 <- (del [x1,x2,x3,x4,x5,x6,x7] [2,4..8]),
			let var7 = var6 * 10 + x8, mod var7 8 == 0,
			x9 <- (del [x1,x2,x3,x4,x5,x6,x7,x8] [1..9]),
			let var8 = var7 * 10 + x9, mod var8 9 == 0]