Permutations with changing number of objects - a sequence with a combination of numeric and alphanumerics

Question

A number sequence generator produces 5 digit codes. I believe that we are getting close to maxing out the codes that it is already issued. I would like to calculate the maximum number of permutations and compare it to the distinct count of permutations that it has already issued.

However, the permutation formulas that I have been reading so far deal only with examples where the number of objects is the same for every sample.

But in my case it is not.

The first character is alphanumeric, however, some letters are not allowed so it has 31 possible values. The second character is alphanumeric so there would be 36 possible values with repetition. The last three values are numeric so they would each only have 10 possible values with repetition.

How would I calculate the maximum permutations of these?

David G. Stork · Accepted Answer · 2019-07-24T17:43:25.677

0

Multiply as in: $31 \cdot 36 \cdot 10^3$.

Recommendation: Your question does not give any information about the number of sequences already issued, and that number is not necessary for solution to the question you asked. Nor does "inheriting" a sequence generator have anything to do with your question. (See why?) Please improve your problem by eliminating such useless and distracting "information."

edited Jul 24 '19 at 17:43

answered Jul 24 '19 at 17:38

David G. Stork

29,774

Hi, thanks for the suggestions and the edit. Let me know if there is anything else I can do to improve the post. – MrGoodfix Jul 24 '19 at 17:47
@MrGoodfix: You can accept (or at least upvote) my correct answer. – David G. Stork Jul 24 '19 at 17:48

Permutations with changing number of objects - a sequence with a combination of numeric and alphanumerics

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