18512792

Appears in sequences

• Number of n-bead necklaces with 2 colors when turning over is not allowed; also number of output sequences from a simple n-stage cycling shift register; also number of binary irreducible polynomials whose degree divides n.at n=29A000031
• Number of subsets of {1,2,...,n} which sum to 0 modulo n.at n=28A063776
• a(n) = (1/n) * Sum_{d divides n} (-1)^(n+d)*phi(n/d)*2^d.at n=28A074763
• Bisection of A000031.at n=14A100447
• a(n) = A159553(n)/n.at n=28A159554
• Number of binary strings of length n that are "prefix heavy", meaning that the fraction of "1" bits in any nonempty prefix is at least as great as the fraction of "1" bits in the entire string.at n=29A298072
• a(n) = ceiling((2^n+n-1)/n).at n=28A373895