Number of sets of nonempty words with a total of n letters over quaternary alphabet.
A292838
Number of sets of nonempty words with a total of n letters over quaternary alphabet.
Terms
- a(0) =1a(1) =4a(2) =22a(3) =132a(4) =729a(5) =4000a(6) =21488a(7) =113760a(8) =594548a(9) =3073392a(10) =15732936a(11) =79846448a(12) =402104884a(13) =2010879968a(14) =9992425872a(15) =49366096352a(16) =242584319710
External references
- oeis: A292838