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1/8 the number of permutations of 3 indistinguishable copies of 1..n with exactly 4 local maxima.
1

%I #6 May 12 2020 12:55:11

%S 0,0,46,22615,5036741,819235874,114962084772,14974498962192,

%T 1876234090571968,230313563301166336,27966954502164518912,

%U 3376705184454377873408,406486565581361073979392,48857132166440216820449280,5867654791849010140880306176,704409107074292841154786361344

%N 1/8 the number of permutations of 3 indistinguishable copies of 1..n with exactly 4 local maxima.

%H Andrew Howroyd, <a href="/A152501/b152501.txt">Table of n, a(n) for n = 1..200</a>

%o (PARI) \\ PeaksBySig defined in A334774.

%o a(n) = {PeaksBySig(vector(n,i,3), [3])[1]/8} \\ _Andrew Howroyd_, May 12 2020

%Y Cf. A152499, A334774.

%K nonn

%O 1,3

%A _R. H. Hardin_, Dec 06 2008

%E Terms a(9) and beyond from _Andrew Howroyd_, May 12 2020