Euler problems/171 to 180

Problem 171

Finding numbers for which the sum of the squares of the digits is a square.

Solution:

problem_171 = undefined

Problem 172

Investigating numbers with few repeated digits.

Solution:

problem_172 = undefined

Problem 173

Using up to one million tiles how many different "hollow" square laminae can be formed? Solution:

problem_173=
    let c=div (10^6) 4
        xm=floor$sqrt $fromIntegral c
        k=[div c x|x<-[1..xm]]
    in  sum k-(div (xm*(xm+1)) 2)

Problem 174

Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements.

Solution:

problem_174 = undefined

Problem 175

Fractions involving the number of different ways a number can be expressed as a sum of powers of 2. Solution:

problem_175 = undefined

Problem 176

Rectangular triangles that share a cathetus. Solution:

problem_176 = undefined

Problem 177

Integer angled Quadrilaterals.

Solution:

problem_177 = undefined

Problem 178

Step Numbers Solution:

problem_178 = undefined

Problem 179

Consecutive positive divisors. Solution:

problem_179 = undefined

Problem 180

Solution:

problem_180 = undefined