nbDig :: Int -> Int -> Int
nbDig n d = sum (map  (\a -> stringDigits (show (a^2)) d) [0..n])
nbDig :: Int -> Int -> Int
nbDig n d = sum (map  (\a -> stringDigits (show (a^2)) d) [0..n])
nbDig n d = sum (map  (\a -> stringDigits (show (a^2)) d) [0..n])