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Number of Dyck paths of semilength n having exactly 3 (possibly overlapping) occurrences of the consecutive steps UDUUDU (with U=(1,1), D=(1,-1)).
2

%I #4 Jun 04 2014 18:18:34

%S 1,9,54,279,1334,6092,27048,117896,507173,2160151,9128266,38326830,

%T 160063712,665442560,2755685897,11372798741,46794914849,192029181971,

%U 786126469079,3211253947191,13091799706905,53277016211285,216451122516387,878040805034630

%N Number of Dyck paths of semilength n having exactly 3 (possibly overlapping) occurrences of the consecutive steps UDUUDU (with U=(1,1), D=(1,-1)).

%H Alois P. Heinz, <a href="/A243415/b243415.txt">Table of n, a(n) for n = 8..550</a>

%Y Column k=3 of A243366.

%K nonn

%O 8,2

%A _Alois P. Heinz_, Jun 04 2014