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CSC 236               Tutorial Exercises for Week  2              Fall 2007
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A.  Prove that it is possible to make every amount of postage of at least
    18c using only 4c and 7c stamps.  Follow the detailed format given in
    lecture -- in particular, define P(n) precisely.

B.  What is the value of SUM_{0 <= i <= n} 2^i?  Make a conjecture and
    prove it, using the format given in lecture.