A293748 Number of sets of nonempty words with a total of n letters over nonary alphabet such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

1, 1, 2, 6, 15, 45, 136, 430, 1415, 4845, 17234, 63497, 242720, 958754, 3916799, 16493831, 71586602, 319336319, 1463096806, 6869041635, 33014439494, 162130576595, 812715417240, 4151894763819, 21595739171153, 114222733829429, 613789962584588, 3347502798880170

Offset: 0

Author

Alois P. Heinz, Oct 15 2017

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..1000

Crossrefs

Column k=9 of A293112.

Cf. A212915, A293739.

Formula

G.f.: Product_{j>=1} (1+x^j)^A212915(j).