The number of words of length n created with the letters a, b, c with at least as many a's as b's and at least as many b's as c's and no adjacent letters forming the pattern aba or bab.
A176148
The number of words of length n created with the letters a, b, c with at least as many a's as b's and at least as many b's as c's and no adjacent letters forming the pattern aba or bab.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =9a(4) =17a(5) =44a(6) =143a(7) =309a(8) =825a(9) =2641a(10) =6036a(11) =16310a(12) =51451a(13) =121475a(14) =330611a(15) =1031592a(16) =2489179a(17) =6806882a(18) =21058747a(19) =51618081a(20) =141626550a(21) =435164141a(22) =1079460430a(23) =2969133001a(24) =9071871281a(25) =22716623921a(26) =62604444233a(27) =190384667595a(28) =480402101159
External references
- oeis: A176148