99880

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=21A000031
• Number of vertex-transitive graphs with n nodes.at n=42A006799
• Number of nonisomorphic circulant graphs, i.e., undirected Cayley graphs for the cyclic group of order n.at n=42A049287
• Number of subsets of {1,2,...,n} which sum to 0 modulo n.at n=20A063776
• Number of subsets of {1,2,3,...,n} that sum to 0 mod 21.at n=21A068042
• a(n) = (1/n) * Sum_{d divides n} (-1)^(n+d)*phi(n/d)*2^d.at n=20A074763
• Bisection of A000031.at n=10A100447
• Symmetrical triangle sequence from polynomials: q(x,n)=(-1)^n*(Sum[(k + 1)^n*x^k/k, {k, 1, Infinity}] + Log[1 - x])*(x - 1)^n/x; p(x,n)=q(x,n)+x^n*q(1/x,n).at n=47A154989
• Number of distinct n X 3 toroidal binary arrays.at n=6A184265
• Number of distinct n X 7 toroidal binary arrays.at n=2A184269
• Table read by antidiagonals: T(n,k) = number of distinct n X k toroidal binary arrays (n >= 1, k >= 1).at n=38A184271
• Table read by antidiagonals: T(n,k) = number of distinct n X k toroidal binary arrays (n >= 1, k >= 1).at n=42A184271
• Number of Cayley graphs on n nodes.at n=42A185959
• Number of circulant graphs on n vertices up to Cayley isomorphism.at n=42A285620
• Number of locally disjoint rooted semi-identity trees with n unlabeled vertices.at n=15A331783