Number of n-length words w over a 6-ary alphabet such that w is empty or a prefix z concatenated with letter a_i and i=1 or 0 < #(z,a_{i-1}) >= #(z,a_i), where #(z,a_i) counts the occurrences of the i-th letter in z.
A240612
Number of n-length words w over a 6-ary alphabet such that w is empty or a prefix z concatenated with letter a_i and i=1 or 0 < #(z,a_{i-1}) >= #(z,a_i), where #(z,a_i) counts the occurrences of the i-th letter in z.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =14a(5) =46a(6) =165a(7) =650a(8) =2742a(9) =12195a(10) =56388a(11) =267382a(12) =1291017a(13) =6304776a(14) =31043333a(15) =153739806a(16) =764663187a(17) =3817811679a(18) =19117378411a(19) =96034890298a(20) =483633087406
External references
- oeis: A240612