30402457

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=42A000043
• 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=26A001153
• a(n) is the n-th term in sequence A_n, respecting the offset, or a(n) = -1 if A_n has fewer than n terms.at n=42A051070
• a(n) is the n-th term of sequence A_n, ignoring the offset, or -1 if A_n has fewer than n terms.at n=42A091967
• Bisection of A000043.at n=21A099982
• Mersenne prime indices that are not Gaussian primes.at n=24A112634
• Primes p such that 2^p-1 is prime and congruent to 31 mod 5!.at n=23A145040
• Primes p (A000043) such that 2^p-1 is prime (A000668) and congruent to 271 mod 6!.at n=8A145044
• Base-2 logarithm of A136007(n)+1.at n=27A152961
• Isolated primes p such that 2^p-1 is also a prime number.at n=26A161676
• Prime numbers n such that 2^n-1 is prime and can be written in the form a^2+7*b^2.at n=22A216518
• Odious Mersenne exponents.at n=23A237499
• Numbers k such that 3*k-4 and 2^k-1 are prime.at n=18A247147
• Numbers m such that 2^m + (-1)^m is prime.at n=46A285929
• 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=19A354168
• Prime numbersat n=1881339