4971068

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=27A000031
• Number of subsets of {1,2,...,n} which sum to 0 modulo n.at n=26A063776
• a(n) = (1/n) * Sum_{d divides n} (-1)^(n+d)*phi(n/d)*2^d.at n=26A074763
• Bisection of A000031.at n=13A100447