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%I #4 Oct 18 2017 19:16:59
%S 1,5,25,102,410,1545,5784,21015,76248,272377,974208,3455177,12287351,
%T 43502174,154554897,547955950,1950335934,6937352521,24777223885,
%U 88515560121,317513893877,1139848959317,4108296484542,14823490668322,53689879422115,194704264528116
%N Number of sets of nonempty words with a total of n letters over quaternary alphabet containing the fourth letter 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="/A293885/b293885.txt">Table of n, a(n) for n = 4..1000</a>
%F a(n) = A293743(n) - A293742(n).
%Y Column k=4 of A293113.
%Y Cf. A293742, A293743.
%K nonn
%O 4,2
%A _Alois P. Heinz_, Oct 18 2017