42643801

Properties

Appears in sequences

• Mersenne exponents: primes p such that 2^p - 1 is prime. Then 2^p - 1 is called a Mersenne prime.at n=45A000043
• Degrees of primitive irreducible trinomials: n such that 2^n - 1 is a Mersenne prime and x^n + x^k + 1 is a primitive irreducible polynomial over GF(2) for some k with 0 < k < n.at n=28A001153
• Bisection of A000043.at n=22A099983
• Mersenne prime indices that are not Gaussian primes.at n=26A112634
• Primes p such that 2^p-1 is prime and congruent to 31 mod 5!.at n=25A145040
• Primes p (A000043) such that 2^p-1 is prime (A000668) and congruent to 271 mod 6!.at n=9A145044
• Base-2 logarithm of A136007(n)+1.at n=29A152961
• Isolated primes p such that 2^p-1 is also a prime number.at n=29A161676
• Prime numbers n such that 2^n-1 is prime and can be written in the form a^2+7*b^2.at n=23A216518
• Let M_p = 2^p-1 be a Mersenne prime, where p is an odd prime. Sequence lists p such that b_{p-2} == -2^((p+1)/2) mod M_p, where {b_k} is defined in the Comments.at n=21A354168
• Prime numbersat n=2584328