A simple context-free grammar in a labeled universe: labeled version of A006318.
A052742
A simple context-free grammar in a labeled universe: labeled version of A006318.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =12a(4) =144a(5) =2640a(6) =64800a(7) =1985760a(8) =72817920a(9) =3105527040a(10) =150907276800
External references
- oeis: A052742