How many unique ordered lists of $N$ integers - $(q_1, ..., q_N)$ - can I form if $q_i \in [0, M]$, and we have the restriction that $\sum_{i=0}^{N} q_i \geq k$?
The number of unique ordered sets of integers over some domain provided that the elements of the set sum to some at least some value $k$
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combinatorics
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0@leonbloy Integers may be equal, however {10, 5} must be counted as distinct from {5, 10}, for example. Yes, regarding the second point. – 2012-12-24
1 Answers
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The number of such lists is the sum of the coefficients of $x^r$ for $r \ge k$ in the expansion of $(1+x+...+x^M)^N.$ There may be a clever way to extract the given sum of coefficients, but I don't see it. Anyway if you have a specific case to calculate, and can use maple or other CAS, the count can be found; maple for example has a function to extract a coeffient of a power of $x$ from an expanded polynomial, and one could code up a function to sum those for $r\ge k$.