A237445 Primes p such that f(f(p)) is prime, where f(x) = x^4 + x^3 + x^2 + x + 1 = A053699(x).
1451, 2351, 2381, 2791, 5531, 5981, 7841, 8821, 10091, 10501, 11411, 11701, 12011, 13241, 15271, 15331, 16691, 17231, 18341, 18671, 19891, 20981, 21911, 23071, 23131, 23561, 23741, 24061, 25321, 27361, 29221, 30851, 30941, 31271, 32141, 33931
Offset: 1
Keywords
Examples
1451 is prime and f(f(1451)) = 387147304469214558406348338836395337085545589397781 is prime. Thus, 1451 is a member of this sequence.
Programs
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PARI
f(x)=x^4+x^3+x^2+x+1;forprime(p=1,35000,ispseudoprime(f(f(p)))&&print1(p",")) \\ M. F. Hasler, Feb 09 2014
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Python
import sympy from sympy import isprime {print(n) for n in range(10**5) if isprime(n) and isprime((n**4+n**3+n**2+n+1)**4+(n**4+n**3+n**2+n+1)**3+(n**4+n**3+n**2+n+1)**2+(n**4+n**3+n**2+n+1)+1)}
Comments