A084837 Palindromic primes with nonincreasing digits up to the middle and then nondecreasing.

2, 3, 5, 7, 11, 101, 313, 727, 757, 919, 929, 31013, 72227, 73037, 73237, 74047, 75557, 76367, 76667, 77377, 77477, 91019, 93139, 93239, 94049, 94349, 96269, 96469, 97379, 97579, 98389, 98689, 3211123, 3222223, 3310133, 3321233, 3331333, 7100017, 7300037, 7310137

Offset

1,1

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Patrick De Geest, World of Palindromic Primes

Prog

(Python)
from sympy import isprime
from itertools import count, islice, combinations_with_replacement as mc
def agen(): # generator of terms
    yield from (2, 3, 5, 7, 11)
    for d in count(2):
        nind = (int("".join(m+m[:-1][::-1])) for m in mc("9876543210", d))
        yield from sorted(filter(isprime, nind))
print(list(islice(agen(), 40))) # Michael S. Branicky, Jun 26 2022

Crossrefs

Cf. A084836, A062351, A062352.

Sequence in context: A222116 A229107 A109574 * A062352 A033938 A069598

Adjacent sequences: A084834 A084835 A084836 * A084838 A084839 A084840

Keyword

nonn,base

Author

Patrick De Geest, Jun 07 2003

Extensions

a(38) and beyond from Michael S. Branicky, Jun 26 2022

Status

approved