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%I #9 Jul 13 2015 19:07:28
%S 0,1,126,1181,4966,14289,32966,65821,118686,198401,312814,470781,
%T 682166,957841,1309686,1750589,2294446,2956161,3751646,4697821,
%U 5812614,7114961,8624806,10363101,12351806,14613889,17173326,20055101,23285206,26890641,30899414,35340541
%N Number of n-ary words beginning with the first character of the alphabet, that can be built by inserting five doublets into the initially empty word.
%H Alois P. Heinz, <a href="/A194717/b194717.txt">Table of n, a(n) for n = 0..1000</a>
%F G.f.: -x*(1+121*x+561*x^2+311*x^3+14*x^4) / (x-1)^5.
%F a(0) = 0, a(n) = 1+(8+(27+(48+42*(n-1))*(n-1))*(n-1))*(n-1) for n>0.
%e a(1) = 1: aaaaaaaaaa (with 1-ary alphabet {a}).
%p a:= n-> `if`(n=0, 0, (x-> 1+(8+(27+(48+42*x)*x)*x)*x)(n-1)):
%p seq(a(n), n=0..40);
%Y Row n=5 of A183134.
%K nonn
%O 0,3
%A _Alois P. Heinz_, Sep 02 2011
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