a(n) is the number of hierarchical linear models on n labeled factors allowing 2-way interactions (but no higher order interactions); or the number of simple labeled graphs with nodes chosen from an n-set.
A006896
a(n) is the number of hierarchical linear models on n labeled factors allowing 2-way interactions (but no higher order interactions); or the number of simple labeled graphs with nodes chosen from an n-set.
Terms
- a(0) =1a(1) =2a(2) =5a(3) =18a(4) =113a(5) =1450a(6) =40069a(7) =2350602a(8) =286192513a(9) =71213783666
External references
- oeis: A006896