87211

Properties

Appears in sequences

• Smallest primitive factor of 2^(2n+1) + 1.at n=13A002185
• Largest prime factor of 2^n + 1.at n=27A002587
• Largest primitive factor of 2^(2n+1) + 1.at n=13A002589
• Number of Barlow packings with group R3(bar)m(O) that repeat after 6n layers.at n=16A011955
• Number of asymmetric rooted polygonal cacti with bridges (mixed Husimi trees).at n=13A035353
• Prime factors of numbers in A006521 (numbers k that divide 2^k + 1).at n=11A057719
• A006530(x)=2 is a local minimum if x=2^n. Running upward with argument x, the largest prime divisor should increase. The value of first peak is a(n).at n=26A102643
• Primes whose logarithms are known to possess binary BBP formulas.at n=38A104885
• a(n) is the least prime such that the multiplicative order of 4 mod a(n) equals n.at n=26A112092
• 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=53A112927
• a(n) = Sum_{k=floor((n+1)/2)..n} J(k+1), J(k) = A001045(k).at n=16A129362
• List of primitive prime divisors of the numbers (4^n-1)/3 (A002450) in their order of occurrence.at n=47A129735
• List of primitive prime divisors of the Jacobsthal numbers A001045 in their order of occurrence.at n=26A129738
• Primes that divide 2^(3^n)+1 for some n.at n=6A136474
• Irregular triangle read by rows: row n gives prime factors of (2^(3^(n+1))+1)/(2^(3^n)+1).at n=4A136475
• Primes which divide none of overpseudoprimes to base 2 (A141232).at n=25A144755
• Primes which are divisors of numbers of the form (2^phi(3^k) - 1)/3^k.at n=12A152008
• A list of primes written in order of their first appearance in a table of prime factorizations of 2^k+1, k=1,2,... .at n=32A158895
• The unique primitive prime factor of 2^n-1 for the n in A161508.at n=32A161509
• Numbers k (between 2^(m-1) and 2^m) such that 2^(k-1) == 1 (mod k) and 2^(k-1-m) == k - 2^p (mod k) for some p > 0 with 2^p < k.at n=20A167612