Number of (undirected) cycles in the graph with nodes labeled 1..n, and nodes i and j joined by an edge if i divides j or vice versa.
A161787
Number of (undirected) cycles in the graph with nodes labeled 1..n, and nodes i and j joined by an edge if i divides j or vice versa.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =6a(6) =6a(7) =18a(8) =25a(9) =42a(10) =42a(11) =241a(12) =241a(13) =324a(14) =667a(15) =1602a(16) =1602a(17) =5511a(18) =5511a(19) =21596a(20) =32549a(21) =35434a(22) =35434a(23) =237727a(24) =270992a(25) =292057a(26) =421656a(27) =1140425a(28) =1140425a(29) =7609789
External references
- oeis: A161787