Number of words w of length n such that each letter of the ternary alphabet is used at least once and for every prefix z of w we have #(z,a_i) = 0 or #(z,a_i) >= #(z,a_j) for all j>i and #(z,a_i) counts the occurrences of the i-th letter in z.
A321839
Number of words w of length n such that each letter of the ternary alphabet is used at least once and for every prefix z of w we have #(z,a_i) = 0 or #(z,a_i) >= #(z,a_j) for all j>i and #(z,a_i) counts the occurrences of the i-th letter in z.
Terms
- a(0) =6a(1) =12a(2) =35a(3) =87a(4) =232a(5) =599a(6) =1591a(7) =4202a(8) =11262a(9) =30221a(10) =81834a(11) =222321a(12) =607871a(13) =1668296a(14) =4601369a(15) =12737394a(16) =35401272a(17) =98716505a(18) =276192166a(19) =774988564a(20) =2180739865a(21) =6151939960a(22) =17396648770a(23) =49303165809a(24) =140018238988a(25) =398407130710
External references
- oeis: A321839