A243401 Primes p such that p^8 - p^7 - p^6 - p^5 - p^4 - p^3 - p^2 - p - 1 is prime.

5, 23, 41, 61, 73, 103, 109, 157, 167, 181, 307, 311, 347, 367, 467, 577, 593, 601, 677, 709, 739, 839, 863, 1039, 1181, 1201, 1279, 1381, 1399, 1621, 1627, 1789, 1847, 1861, 1871, 1913, 1997, 2063, 2287, 2347, 2371, 2657, 2699, 2797, 2887, 2963, 3209, 3343, 3359, 3623

Offset

1,1

Links

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

Example

5 is prime and 5^8 - 5^7 - 5^6 - 5^5 - 5^4 - 5^3 - 5^2 - 5 - 1 = 292969 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**8-n**7-n**6-n**5-n**4-n**3-n**2-n-1) and isprime(n)}
(PARI) for(n=1, 10^4, if(ispseudoprime(n)&&ispseudoprime(n^8-sum(i=0, 7, n^i)), print1(n, ", ")))

Crossrefs

Cf. A243297.

Sequence in context: A044447 A242215 A061240 * A062341 A176251 A293533

Adjacent sequences: A243398 A243399 A243400 * A243402 A243403 A243404

Keyword

nonn

Author

Derek Orr, Jun 04 2014

Status

approved