43691

Properties

Appears in sequences

• Wagstaff primes: primes of form (2^p + 1)/3.at n=5A000979
• Jacobsthal sequence (or Jacobsthal numbers): a(n) = a(n-1) + 2*a(n-2), with a(0) = 0, a(1) = 1; also a(n) = nearest integer to 2^n/3.at n=17A001045
• Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), with repetition.at n=35A001269
• Smallest primitive factor of 2^(2n+1) + 1.at n=8A002185
• Largest prime factor of 2^n + 1.at n=17A002587
• Largest primitive factor of 2^(2n+1) + 1.at n=8A002589
• Divisors of 2^34 - 1.at n=2A003541
• a(2*n) = 2*a(2*n-1), a(2*n+1) = 2*a(2*n)-1.at n=17A005578
• a(n) = (2^(2^n + 1) + 1)/3.at n=3A006485
• a(n) = (2^(2*n + 1) + 1)/3.at n=8A007583
• Numbers n such that game of n X n Button Madness need have no solution; this lists only the primitive elements of the set.at n=13A007802
• Cyclotomic polynomials at x=2.at n=34A019320
• Cyclotomic polynomials at x=-2.at n=17A020501
• a(n) = C(n,0) + C(n,3) + ... + C(n,3[n/3]).at n=17A024493
• a(n) = C(n,2) + C(n,5) + ... + C(n, 3*floor(n/3)+2).at n=17A024495
• Primes in the Jacobsthal sequence (A001045).at n=6A049883
• Grundy function for turn-at-most-9-coins game.at n=19A054046
• a(n) = (2^n - 1)/product(2^p - 1) where the product is over all distinct primes p that divide n.at n=33A055515
• Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), without repetition.at n=30A060444
• 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=33A064078