how many can be formed?

and is it possible to insert constraints like these :

max of consonants in a row : 6 ( but the same can't be repeated consecutively more than twice = ss ttt mmm bbbb etc .. but if interwoven it is ok : archchronicler , schylds , wppwrmwste etc )

max of vowels in a row : 5 ( but the same can't be repeated consecutively more than twice = aaa iiii uuuuu etc .. but if interwoven it is ok : queueing etc )

would there be a formula for it?
 
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