Number of n-length words w over an n-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.
A240617
Number of n-length words w over an n-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) =651a(8) =2771a(9) =12638a(10) =61398a(11) =315563a(12) =1710027a(13) =9725543a(14) =57886132a(15) =359476571a(16) =2323518017a(17) =15597303757a(18) =108522502933a(19) =781283103284
External references
- oeis: A240617