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%I #10 Sep 01 2015 10:45:59
%S 1,9,126,1704,22986,310086,4183260,56435004,761346207,10271072557,
%T 138563678736,1869317246556,25218347263608,340212470558832,
%U 4589695110222504,61918074814238448,835316485437693186,11268981358631127288,152026139882340589466
%N Number of 9-compositions of n: matrices with 9 rows of nonnegative integers with positive column sums and total element sum n.
%C Also the number of compositions of n where each part i is marked with a word of length i over a nonary alphabet whose letters appear in alphabetical order.
%H Alois P. Heinz, <a href="/A261801/b261801.txt">Table of n, a(n) for n = 0..880</a>
%F G.f.: (1-x)^9/(2*(1-x)^9-1).
%F a(n) = A261780(n,9).
%p a:= proc(n) option remember; `if`(n=0, 1,
%p add(a(n-j)*binomial(j+8, 8), j=1..n))
%p end:
%p seq(a(n), n=0..20);
%Y Column k=9 of A261780.
%K nonn,easy
%O 0,2
%A _Alois P. Heinz_, Sep 01 2015
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