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A085300 a(n) is the least prime x such that when reversed it is a power of prime(n). 3
2, 3, 5, 7, 11, 31, 71, 163, 18258901387, 90367894271, 13, 73, 1861, 344800741, 34351783286302805384336021, 940315563074788471, 1886172359328147919771, 14854831 (list; graph; refs; listen; history; text; internal format)
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

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Last modified July 23 13:49 EDT 2019. Contains 325254 sequences. (Running on oeis4.)