A simple context-free grammar in a labeled universe: labeled version of A052706.
A052729
A simple context-free grammar in a labeled universe: labeled version of A052706.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =12a(4) =168a(5) =3120a(6) =75600a(7) =2237760a(8) =78382080a(9) =3169393920a(10) =145297152000
External references
- oeis: A052729