# Project Euler #004

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 99. Find the largest palindrome made from the product of two 3-digit numbers.

```
let rec reverse (s:string) =
if s.Length = 1 then s
else (reverse (s.Substring 1)) + (s.[0] |> string)
let is_palindrome n = (n |> string) = reverse (n |> string)
[100..999] |> List.collect (fun x -> [100..999] |> List.map (fun y -> x * y))
|> List.filter (fun x -> is_palindrome x)
|> List.max
```

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