Compute the least positive integer n for which 10n+1 and 10n+9 are prime but 10n+3 and 10n+7 are composite.
Source: ARML Local 2020
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Zach Marinovhttps://etonstem.com/author/zach
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Zach Marinovhttps://etonstem.com/author/zach
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Zach Marinovhttps://etonstem.com/author/zach
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Zach Marinovhttps://etonstem.com/author/zach
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