A084836 Palindromic primes with nondecreasing digits up to the middle and then nonincreasing.

2, 3, 5, 7, 11, 131, 151, 181, 191, 353, 373, 383, 787, 797, 11311, 11411, 12421, 12721, 12821, 13331, 13831, 13931, 14741, 15551, 16661, 17971, 19991, 33533, 34543, 34843, 35753, 77977, 78887, 79997, 1114111, 1117111, 1123211, 1126211, 1129211, 1134311

Offset: 1

Author

Patrick De Geest, Jun 07 2003

Keywords

• nonn
• base

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000
• Patrick De Geest, World of Palindromic Primes

Crossrefs

Cf. A084837, A062351, A062352.

Programs

Python

from sympy import isprime
from itertools import count, islice, combinations_with_replacement as mc
def agen():
    yield from (2, 3, 5, 7, 11)
    for d in count(2):
        ndni = (int("".join(m+m[:-1][::-1])) for m in mc("123456789", d))
        yield from filter(isprime, ndni)
print(list(islice(agen(), 40))) # Michael S. Branicky, Jun 26 2022

Extensions

a(39) and beyond from Michael S. Branicky, Jun 26 2022