Consider the sequence that begins 101, 113, 127, 131, 149, 151, 163,... Not only is every term prime, the nth term is the smallest prime with n in the interior digits.
Write a function that takes an integer and returns the smallest prime with that integer in its interior.
Although it's not part of the problem, you might think about these questions and others: Which terms are formed by adding 1s to the beginning and end? Which value of n results in a prime that requires more than one digit added to beginning and end? Does the sequence include any terms starting and ending with 9?
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Last Solution submitted on Jul 17, 2026

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