Nice recursive solution. I didn't think of this solution. It took me some time to understand what the creator of the Kata meant. The description was kinda vague.

It is a good solution. I would suggest that you do: input.ToLower() .ToCharArray() .ToList() etc. Then you have more readable code. If you look at my solution you see how it can be achieved without using the dictionary. But it is still a good solution :-)

Thanks. I like your implementation of extension methods. Makes a lot of sense and allows a first-to-last method call notation rather than the last-to-first one I am forced to use.

Your solution looks almost as mine only i would recommend to implement the transformations as extensions :) looks more clean. For the rest good job!

Sweet! Same solution :)

Thank you for pointing that out! I'll have a look ...

Thanks! Most interesting thing I learned about here, was the use of the (?i) in a Regex, to make it act case insensitive.
It is like the /...../i in Perl, which I really missed and for which I really disliked using the extra RegexOptions.IgnoreCase argument.
Info on that can be found at: https://msdn.microsoft.com/en-us/library/yd1hzczs.aspx

Damn, I didn't think about this approach. This is going to my favourites! Love the LINQ style :-) ...

Thanks! My goal was to make the entrance code as clean as possible and really easy to read.

Quite a big solution for the type of problem, but nicely partitioned and easy to read.
And best of all: when you had written your own unit tests, then this structure would have worked well for a TDD approach.

Good point, its indeed a sum and not an assignment.

A small remark: variable 'consecutives' did put me off a bit during my first read through.
I expected that to be a list of, well... consecutives.
It could have been named something like 'summedConsecutives' to make it represent its actual contents better.

Same solution? Ha! Ur looks fine to me as well :-)!

Thanks for the feedback, good point. I wasn't aware of that.

The grouping inside the loop is a bit confusing:

        binaryCalculation *= 2;
      
        if (binaryCalculation == 0)
          binaryCalculation = 1;
        if (BinaryArray[i] != 0)
          binaryRepresentation += binaryCalculation;

The first three lines are about making up the value for binaryCalculation, so they should be grouped:

        binaryCalculation *= 2;
        if (binaryCalculation == 0)
          binaryCalculation = 1;
          
        if (BinaryArray[i] != 0)
          binaryRepresentation += binaryCalculation;

Looking at those three lines, things can be simplified a bit.
When assigning the value 1 at the start of the function to binaryCalculation, the multiplication can be moved to the end of the loop:

        if (BinaryArray[i] != 0)
          binaryRepresentation += binaryCalculation;
          
        binaryCalculation *= 2;

Regards,
Maurice