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A288541 Number of Dyck paths of semilength n such that the minimal number of peaks over all positive levels equals two.

%I A288541 #6 Jun 11 2017 20:44:59
%S A288541 1,0,0,3,13,30,61,172,619,2241,7736,25786,85315,286653,986444,3465777,
%T A288541 12342188,44275218,159463056,576136367,2089063623,7607265038,
%U A288541 27829092314,102263653872,377340952123,1397457667346,5192248524833,19348310336881,72292940817636
%N A288541 Number of Dyck paths of semilength n such that the minimal number of peaks over all positive levels equals two.
%H A288541 Alois P. Heinz, <a href="/A288541/b288541.txt">Table of n, a(n) for n = 2..300</a>
%H A288541 Wikipedia, <a href="https://en.wikipedia.org/wiki/Lattice_path#Counting_lattice_paths">Counting lattice paths</a>
%e A288541 : a(5) = 3:
%e A288541 :
%e A288541 :            /\/\      /\/\      /\/\
%e A288541 :       /\/\/    \  /\/    \/\  /    \/\/\  .
%Y A288541 Column k=2 of A288387.
%Y A288541 Cf. A000108.
%K A288541 nonn
%O A288541 2,4
%A A288541 _Alois P. Heinz_, Jun 11 2017