I think I'm finished with the anagrams except for the cases where no two consecutive letters of a given type can appear together.

For example: ABCDEEFFGGHHH

I want to find the number of arrangements that don't contain two consecutive letters H.

So: (All possible anagrams)

- (the ones with 3 consecutive Hs)

- (the ones with 2 consecutive Hs)

+ (cases of 2 consecutive Hs where the "floating" H is adjacent)

Assuming this is correct, is there a cleaner/simpler way to do it?