

A243400


Primes p such that p^6  p^5  p^4  p^3  p^2  p  1 is prime.


0



5, 7, 17, 37, 79, 157, 239, 269, 277, 359, 419, 449, 467, 557, 677, 739, 787, 829, 857, 977, 1319, 1399, 1597, 1657, 2069, 2269, 2297, 2377, 2437, 2459, 2819, 2969, 2999, 3019, 3137, 3299, 3389, 3407, 3967, 4007, 4099, 4357, 4547, 4729, 4987, 5179, 5419, 5569, 5779, 6637
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OFFSET

1,1


COMMENTS

a(1) = 5 is the only term that ends in a 5. It is unknown if any term will end in a 3 or 1.


LINKS

Table of n, a(n) for n=1..50.


EXAMPLE

5 is prime and 5^6  5^5  5^4  5^3  5^2  5  1 = 11719 is prime. Thus 5 is a member of this sequence.


PROG

(Python)
import sympy
from sympy import isprime
{print(n, end=', ') for n in range(10**4) if isprime(n**6n**5n**4n**3n**2n1) and isprime(n)}
(PARI) for(n=1, 10^4, if(ispseudoprime(n)&&ispseudoprime(n^6sum(i=0, 5, n^i)), print1(n, ", ")))


CROSSREFS

Cf. A243300.
Sequence in context: A272717 A018538 A038968 * A318568 A239414 A163570
Adjacent sequences: A243397 A243398 A243399 * A243401 A243402 A243403


KEYWORD

nonn


AUTHOR

Derek Orr, Jun 04 2014


STATUS

approved



