A152517 - OEIS

%I #7 May 10 2020 23:03:56

%S 0,3,412,50080,6016512,722051072,86646800384,10397622337536,

%T 1247714738176000,149725769101213696,17967092296776155136,

%U 2156051075653940805632,258726129078829378961408,31047135489462617851822080,3725656258735540805375623168,447078751048265125343493357568

%N 1/56 of the number of permutations of 7 indistinguishable copies of 1..n with exactly 2 local maxima.

%H Andrew Howroyd, <a href="/A152517/b152517.txt">Table of n, a(n) for n = 1..200</a>

%F a(n) = (13*120^(n-1) - 13*8^(n-1) - 14*(n-1)*8^(n-1))/448. - _Andrew Howroyd_, May 10 2020

%o (PARI) a(n) = {(13*120^(n-1) - 13*8^(n-1) - 14*(n-1)*8^(n-1))/448} \\ _Andrew Howroyd_, May 10 2020

%Y Cf. A152494, A334773.

%K nonn

%O 1,2

%A _R. H. Hardin_, Dec 06 2008

%E Terms a(7) and beyond from _Andrew Howroyd_, May 10 2020