Maths Olympiad Prep

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Number theory Difficulty 4.8 AIME Find the answer

Our next object up for bid is an arithmetic progression of primes. For example, the primes 3,5, and 7 form an arithmetic progression of length 3. What is the largest possible length of an arithmetic progression formed of positive primes less than 1,000,000? Be prepared to justify your answer.

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

12. We can get 12 with 110437 and difference 13860.

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Source: Omni-MATH, licensed Apache-2.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.