A321843 Number of words w of length n such that each letter of the septenary 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.
5040, 20160, 105840, 438480, 1941390, 7981380, 34199295, 143278023, 618279060, 2662235895, 11732993885, 52051997928, 235469637340, 1076082576890, 5001152965060, 23506245393141, 112121385673903, 540819706031799, 2642597365003695, 13049933076792172
Offset: 7
Keywords
Crossrefs
Column k=7 of A257783.