Berkeley Math Circle: Monthly Contest 8 #0hx1
Berkeley Math Circle: Monthly Contest 8Hard
From module Euler's Totient Theorem
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Understand the scale
Scale
0.5: Easiest math competition problems, often solvable even for early middle school students without experience.
1: Problems strictly for beginners, often at a moderate middle school level.
1.5: Problems for stronger beginner students, on the level of the middling problems in most middle school contests.
2: For motivated beginners, harder questions from the previous categories.
2.5: More advanced beginner problems, hardest questions from previous categories.
3: Early intermediate problems that require more creative thinking.
3.5: Tougher early intermediate problems that consistently stretch into higher-level creative thinking or conceptual knowledge.
4: Intermediate-level problems.
4.5: Upper intermediate problems approaching the upper bound for non-invitational sprint math competitions.
5: More difficult AIME problems or simple proof-based Olympiad-style problems.
6: High-level AIME-styled questions or introductory Olympiad-level questions.
7: Tougher Olympiad-level questions, may require more technical knowledge.
8: High-level Olympiad-level questions.
9: Expert Olympiad-level questions.
9.5: The hardest problems appearing on Olympiads which the strongest students could reasonably solve.
10: Historically notorious problems, generally unsuitable for even very hard competitions because they are exceedingly tedious, long, and difficult.
φ (Euler's totient)Greatest common divisors (gcd)Prime numbers
Problem
Problem:
In the pattern shown below, row 1 (the bottom row) consists of two 's, and row is formed by taking row and inserting between each adjacent pair of numbers and their sum :
| 1 | 5 | 4 | 7 | 3 | 8 | 5 | 7 | 2 | 7 | 5 | 8 | 3 | 7 | 4 | 5 | 1 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 4 | 3 | 5 | 2 | 5 | 3 | 4 | 1 | ||||||||
| 1 | 3 | 2 | 3 | 1 | ||||||||||||
| 1 | 2 | 1 | ||||||||||||||
| 1 | 1 | |||||||||||||||
| 1 |
In row 2019 of the pattern, how many copies of 2019 will there be?