Number of multisets of nonempty words with a total of n letters over quaternary alphabet containing the fourth letter such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.
A293799
Number of multisets of nonempty words with a total of n letters over quaternary alphabet containing the fourth letter such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.
Terms
- a(0) =1a(1) =5a(2) =26a(3) =107a(4) =439a(5) =1663a(6) =6283a(7) =22912a(8) =83507a(9) =298936a(10) =1071564a(11) =3804461a(12) =13542785a(13) =47964338a(14) =170456957a(15) =604293910a(16) =2150604057a(17) =7647190962a(18) =27302834888a(19) =97491596984a(20) =349544018586
External references
- oeis: A293799