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A288321 Number of Dyck paths of semilength n such that each positive level has exactly five peaks.

%I A288321 #8 Jun 02 2018 10:37:09
%S A288321 1,0,0,0,0,1,0,0,0,0,0,6,84,336,504,252,0,36,1134,15960,130536,700560,
%T A288321 2639952,7260840,14894712,23151996,29957760,60579792,319505760,
%U A288321 1930565232,9852185196,41993000532,151747572312,471322972512,1275430904496,3072333948480
%N A288321 Number of Dyck paths of semilength n such that each positive level has exactly five peaks.
%H A288321 Alois P. Heinz, <a href="/A288321/b288321.txt">Table of n, a(n) for n = 0..1000</a>
%H A288321 Wikipedia, <a href="https://en.wikipedia.org/wiki/Lattice_path#Counting_lattice_paths">Counting lattice paths</a>
%p A288321 b:= proc(n, k, j) option remember;
%p A288321      `if`(n=j, 1, add(b(n-j, k, i)*(binomial(i, k)
%p A288321       *binomial(j-1, i-1-k)), i=1..min(j+k, n-j)))
%p A288321     end:
%p A288321 a:= n-> `if`(n=0, 1, b(n, 5$2)):
%p A288321 seq(a(n), n=0..35);
%t A288321 b[n_, k_, j_] := b[n, k, j] = If[n == j, 1, Sum[b[n - j, k, i]*(Binomial[i, k]*Binomial[j - 1, i - 1 - k]), {i, 1, Min[j + k, n - j]}]];
%t A288321 a[n_] := If[n == 0, 1, b[n, 5, 5]];
%t A288321 Table[a[n], {n, 0, 35}] (* _Jean-François Alcover_, Jun 02 2018, from Maple *)
%Y A288321 Column k=5 of A288318.
%Y A288321 Cf. A000108.
%K A288321 nonn
%O A288321 0,12
%A A288321 _Alois P. Heinz_, Jun 07 2017