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수악중독

HMMT 2015 Algebra #4 본문

HMMT/2015

HMMT 2015 Algebra #4

수악중독 2015. 3. 15. 13:39

Compute the number of sequences of integers (a1,  ,  a200)(a_1, \; \cdots ,\; a_{200}) such taht th following conditions hold.

  • 0a1<a2<<a2002020 \le a_1 < a_2 < \cdots < a_{200} \le 202.

  • There exists a positive integer NN with the following property: for every index i{1,  ,  200}i \in \{ 1, \; \cdots ,\; 200 \} there exists an index j{1,  ,  200} j \in \{1, \; \cdots ,\; 200\} such that ai+ajNa_i +a_j -N is divisible by 203203.