Euler42

// F# Solution (ugly):
    let mapArray s =
        ([|1.0..500.0|] 
            |> Array.map(fun p -> p/2.0*(p+1.0))) 
            |> Array.filter (fun e->e=(s |> Array.sum)) 
            |> Array.length

    let problem42() =
         let client = new System.Net.WebClient()
         client.DownloadString("https://projecteuler.net/project/resources/p042_words.txt").ToUpper().Replace("\"", "").Split([|','|]) 
                |> Array.map (fun c -> c.ToCharArray() 
                                    |> Array.map (fun l -> (float)l-64.0)) 
                |> Array.map (fun a->mapArray a) |> Array.sum
                
// C# Solution:

File.ReadAllText("w")
  .ToUpper()
  .Replace("\"", "")
  .Split(',')
  .Select(x => x.ToCharArray().Select(l => l - 64))
  .Count(c => Enumerable.Range(1, 500)
      .Select(i => i/2F*(i + 1))
      .Contains(c.Sum()));

Coded triangle numbers
Problem 42
The nth term of the sequence of triangle numbers is given by, tn = ½n(n+1); so the first ten triangle numbers are:

1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...

By converting each letter in a word to a number corresponding to its alphabetical position and adding these values we form a word value. For example, the word value for SKY is 19 + 11 + 25 = 55 = t10. If the word value is a triangle number then we shall call the word a triangle word.

Using words.txt (right click and 'Save Link/Target As...'), a 16K text file containing nearly two-thousand common English words, how many are triangle words?