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Inserting any digit d between adjacent digits of this palindromic prime never produces a new prime. [De Geest] The minimum palindromic prime p such that p + 1 each has exactly 4 distinct prime factors. [Das] The smallest palindromic prime with five embedded primes: 3331, 331, 31, 13 and 3. [Necula] The sum of the squares of three consecutive odd triangular numbers (45^2 + 55^2 + 91^2). Note the three 3's in the middle. [Silva] The smallest palindromic prime in the form 'primedemirp'. '13d31' is a palindromic prime for d = 3, 8, and 9. Curiously, 389 is also an emirp. [Green] The largest prime formed by inserting d identical digits d, between two identical digits n, (d=3, n=1). Note that there are only two other such primes; 313 and 919. [Loungrides]
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