A085300 a(n) is the least prime x such that when reversed it is a power of prime(n).

2, 3, 5, 7, 11, 31, 71, 163, 18258901387, 90367894271, 13, 73, 1861, 344800741, 34351783286302805384336021, 940315563074788471, 1886172359328147919771, 14854831

Offset

1,1

Comments

A006567 (after rearranging terms) and A002385 are subsequences. - Chai Wah Wu, Jun 02 2016

Links

Chai Wah Wu, Table of n, a(n) for n = 1..86

Example

a(14)=344800741 means that 147008443=43^5=p(14)^5, where 5 is the smallest such exponent;
a(19) has 82 decimal digits and if reversed equals 39th power of p(19)=67.

Prog

(Python)
from sympy import prime, isprime
def A085300(n):
    p = prime(n)
    q = p
    while True:
        m = int(str(q)[::-1])
        if isprime(m):
            return(m)
        q *= p # Chai Wah Wu, Jun 02 2016

Crossrefs

Cf. A085298, A057708, A058993, A056994, A059695, A003459, A007500, A055387, A061461, A068652.

Sequence in context: A118495 A028906 A118496 * A119388 A093487 A067933

Adjacent sequences: A085297 A085298 A085299 * A085301 A085302 A085303

Keyword

base,nonn

Author

Labos Elemer, Jun 24 2003

Status

approved