a(n) is the number of top-down sequences (F_1, F_2, ..., F_n) whereas each F_i is a labeled forest on n nodes, containing i directed rooted trees. F_(i+1) is proper subset of F_i.
A152684
a(n) is the number of top-down sequences (F_1, F_2, ..., F_n) whereas each F_i is a labeled forest on n nodes, containing i directed rooted trees. F_(i+1) is proper subset of F_i.
Terms
- a(0) =1a(1) =2a(2) =18a(3) =384a(4) =15000a(5) =933120a(6) =84707280a(7) =10569646080
External references
- oeis: A152684