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A308316
Numbers m such that q = 2^m - 1 and r = m^2 + m + 1 are both primes.
0
2, 3, 5, 17, 89, 9689, 11213, 2976221
OFFSET
1,1
COMMENTS
All terms are primes.
Mersenne exponents p from A000043 such that p^2 + p + 1 is a prime.
Intersection of A000043 and A002384.
Corresponding values of primes q: 3, 7, 31, 131071, 618970019642690137449562111, ...
Corresponding values of primes r: 7, 13, 31, 307, 8011, 93886411, 125742583, 8857894417063, ...
PROG
(Magma) [m: m in [1..1000] | IsPrime(2^m - 1) and IsPrime(m^2 + m + 1)]
(PARI) isok(n) = isprime(2^n-1) && isprime(n^2+n+1); \\ Michel Marcus, May 21 2019
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Jaroslav Krizek, May 19 2019
STATUS
approved