1857283155

Appears in sequences

• Number of n-bead necklaces with beads of 2 colors and primitive period n, when turning over is not allowed but the two colors can be interchanged.at n=37A000048
• Lerch's function q_2(n) = (2^{phi(t)} - 1)/t where t = 2*n - 1.at n=18A001226
• a(n) = floor(2^(n-1)/n).at n=36A006788
• Fermat quotients: (2^(p-1)-1)/p, where p=prime(n).at n=10A007663
• Number of Hamiltonian cycles in the directed graph with 2n nodes {0..2n-1} and edges from each i to 2i (mod 2n) and to 2i+1 (mod 2n).at n=36A027362
• Number of binary Lyndon words with an even number of 1's.at n=36A051841
• Nearest integer to 2^(n-1)/n.at n=36A054650
• Number of n-bead necklace structures using exactly two different colored beads.at n=36A056295
• Number of primitive (period n) n-bead necklace structures using exactly two different colored beads.at n=36A056303
• Number of orbits of length n under a map whose periodic points are counted by A027306.at n=36A060172
• Number of orbits of length n in a map whose periodic points come from A059991.at n=36A060481
• Number of aperiodic necklaces with n red or blue beads such that two necklaces are equivalent under the operation of simultaneously turning the necklace over and switching the two colors.at n=36A066313
• Number of cycles of length n under the mapping x -> x^2-2 modulo Fermat prime 2^(2^m)+1, where m is any fixed integer such that n divides 2^m-1.at n=18A131203
• a(n) = (2^A002326(n)-1)/(2*n+1).at n=18A165781
• a(n) = floor((1 + 4^n)/(1 + 2*n)).at n=17A191637
• a(n) = (1/n)*A204983(n).at n=36A204984
• Numerators of (2^n - 1 + (-1)^n)/(2*n), n > 0.at n=36A254522
• Carmichael quotients to base 2: a(n) = (2^lambda(2*n-1)-1)/(2*n-1), where lambda is the Carmichael lambda function (A002322).at n=18A329238
• Number of n-bead bracelets using exactly three colors with no adjacent beads having the same color.at n=36A330632
• a(n) is the smallest positive integer k such that 1 + k * prime(n) is a power of two.at n=10A352232