Difference between revisions of "2016 IMO Problems/Problem 4"

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==Problem==
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A set of positive integers is called ''fragrant'' if it contains at least two elements and each of its elements has a prime factor in common with at least one of the other elements.  Let <math>P(n)=n^2+n+1</math>.  What is the least possible positive integer value of <math>b</math> such that there exists a non-negative integer <math>a</math> for which the set <math>\{P(a+1),P(a+2),\ldots,P(a+b)\}</math> is fragrant?
 
A set of positive integers is called ''fragrant'' if it contains at least two elements and each of its elements has a prime factor in common with at least one of the other elements.  Let <math>P(n)=n^2+n+1</math>.  What is the least possible positive integer value of <math>b</math> such that there exists a non-negative integer <math>a</math> for which the set <math>\{P(a+1),P(a+2),\ldots,P(a+b)\}</math> is fragrant?
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==Solution==
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{{solution}}
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==See Also==
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{{IMO box|year=2016|num-b=3|num-a=5}}

Revision as of 00:36, 19 November 2023

Problem

A set of positive integers is called fragrant if it contains at least two elements and each of its elements has a prime factor in common with at least one of the other elements. Let $P(n)=n^2+n+1$. What is the least possible positive integer value of $b$ such that there exists a non-negative integer $a$ for which the set $\{P(a+1),P(a+2),\ldots,P(a+b)\}$ is fragrant?

Solution

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See Also

2016 IMO (Problems) • Resources
Preceded by
Problem 3
1 2 3 4 5 6 Followed by
Problem 5
All IMO Problems and Solutions