599479

Properties

Appears in sequences

• a(n) = least primitive factor of 2^(2n+1) - 1.at n=16A002184
• a(n) = largest noncomposite factor of 2^(2n+1) - 1.at n=16A002588
• Divisors of 2^33 - 1.at n=8A003540
• Largest prime factor of 2^n - 1.at n=31A005420
• Cyclotomic polynomials at x=2.at n=33A019320
• a(n) = (2^n - 1)/product(2^p - 1) where the product is over all distinct primes p that divide n.at n=32A055515
• Zsigmondy numbers for a = 2, b = 1: Zs(n, 2, 1) is the greatest divisor of 2^n - 1 (A000225) that is coprime to 2^m - 1 for all positive integers m < n.at n=32A064078
• Quotient of A000225 and A064084.at n=32A064085
• Condensed version of A064085: all terms of A064085 with values greater than 1 (which coincides with all terms of A064085 with nonprime power index).at n=13A064086
• Highest prime dividing the least n-multiperfect number (A007539).at n=5A072002
• Let Cn(x) be the n-th cyclotomic polynomial; a(n) is the first prime Cn(x) after Cn(1).at n=32A085399
• For p = prime(n), a(n) is the largest prime q such that pq is a base-2 pseudoprime; that is, 2^(pq-1) = 1 mod pq; a(n) is 0 if no such prime exists.at n=17A086019
• Prime partial sums of the even-indexed primes.at n=26A096207
• Largest primitive prime factor of 2^n-1, or a(n) = 1 if no such prime exists.at n=32A097406
• A006530(x)=2 is a local minimum if x=2^n. Running downward with argument x started at 2^n, the largest prime divisor should increase. The value of first peak is a(n).at n=32A102644
• Sort the primes (except 2) according to the multiplicative order of 2 modulo that prime. If two primes have the same order of 2, they are arranged numerically.at n=36A108974
• Numbers of the form (2^(i*j)-1)/((2^i-1)*(2^j-1)) where gcd(i,j) = 1.at n=18A112674
• a(n) is the least prime such that the multiplicative order of 2 mod a(n) equals n, or a(n)=1 if no such prime exists.at n=32A112927
• Numbers k such that A003313(k) = A003313(7*k).at n=23A116462
• Numbers of the form (2^(p*q)-1) /((2^p-1)*(2^q-1)), where p>q are primes.at n=9A140803