A086757 - OEIS

A086757

Smallest prime p such that n is a palindrome in base-p representation.

2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 13, 5, 3, 13, 2, 3, 2, 5, 23, 3, 2, 23, 3, 5, 29, 3, 2, 3, 31, 29, 2, 7, 2, 37, 37, 5, 41, 37, 41, 3, 5, 13, 47, 43, 2, 5, 53, 7, 53, 7, 2, 3, 59, 17, 59, 3, 5, 59, 61, 11, 67, 5, 2, 7, 2, 67, 5, 3, 71, 13, 7, 5, 2, 73, 79, 37, 79, 5, 83, 3, 83, 3, 5, 11, 2

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OFFSET

1,1

COMMENTS

A016026(n) <= a(n) <= A007918(n).

LINKS

Table of n, a(n) for n=1..85.

PROG

(Python)

from sympy import sieve

from sympy.ntheory import is_palindromic

def a086757(n): return next(p for p in sieve if is_palindromic(n, p)) # Dumitru Damian, Jan 29 2024