OFFSET
1,1
COMMENTS
All numbers are congruent to 2 mod 10, 6 mod 10, or 8 mod 10.
x^5 - Phi_5(x) = x^5-x^4-x^3-x^2-x-1.
EXAMPLE
122 = 3^5-3^4-3^3-3^2-3^1-1 (3 is prime) and 122^5-122^4-122^3-122^2-122^1-1 = 26803717321 is prime. Thus, 122 is a member of this sequence.
PROG
(Python)
import sympy
from sympy import isprime
def poly5(x):
..if isprime(x):
....f = x**5-x**4-x**3-x**2-x-1
....if isprime(f**5-f**4-f**3-f**2-f-1):
......return True
..return False
x = 1
while x < 10**5:
..if poly5(x):
....print(x**5-x**4-x**3-x**2-x-1)
..x += 1
CROSSREFS
KEYWORD
nonn
AUTHOR
Derek Orr, Feb 10 2014
STATUS
approved