Honaker's constant | palprime

A palindromic prime is a number that is simultaneously palindromic and prime. The first few (base-10) palindromic primes are 2, 3, 5, 7, 11, 101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 757, 787, ... (OEIS A002385; Beiler 1964, p. 228). The number of palindromic primes less than a given number are illustrated in the plot above. The number of palindromic numbers having n = 1, 2, 3, ... digits are 4, 1, 15, 0, 93, 0, 668, 0, 5172, 0, ... (OEIS A016115; De Geest) and the total number of palindromic primes less than 10, 10^2, 10^3, ... are 4, 5, 20, 20, 113, 113, 781, ... (OEIS A050251). Gupta has computed the numbers of palindromic primes up to 10^21. The following table lists palindromic primes in various small bases.

Belphegor prime | palindromic number | prime number