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%I #5 Oct 15 2017 17:08:32
%S 1,1,2,6,15,45,136,430,1415,4845,17234,63497,242720,958754,3916799,
%T 16493831,71586602,319336319,1463096806,6869041635,33014439494,
%U 162130576595,812715417240,4151894763819,21595739171153,114222733829429,613789962584588,3347502798880170
%N 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.
%H Alois P. Heinz, <a href="/A293748/b293748.txt">Table of n, a(n) for n = 0..1000</a>
%F G.f.: Product_{j>=1} (1+x^j)^A212915(j).
%Y Column k=9 of A293112.
%Y Cf. A212915, A293739.
%K nonn
%O 0,3
%A _Alois P. Heinz_, Oct 15 2017