A simple context-free grammar in a labeled universe: labeled version of A052705.
A052728
A simple context-free grammar in a labeled universe: labeled version of A052705.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =12a(4) =168a(5) =2880a(6) =64080a(7) =1723680a(8) =54633600a(9) =1992936960a(10) =82261267200
External references
- oeis: A052728