A226287 - OEIS

%I #13 Jul 12 2024 16:39:18

%S 0,0,0,0,0,0,0,0,0,0,0,518400,25401600,1244678400,39829708800,

%T 1274550681600,34412868403200,929147446886400,23228686172160000,

%U 580717154304000000,14053355134156800000,340091194246594560000

%N a(n) = [n/2]!*[(n+1)/2]!*C([n/2],6)*C([(n+1)/2],6).

%C Number of permutations of n elements with 12 odd displacements.

%C Column 7 of A226288.

%C Column k=12 of A145893, a diagonal of A145894. - _Alois P. Heinz_, May 29 2014

%H R. H. Hardin, <a href="/A226287/b226287.txt">Table of n, a(n) for n = 1..210</a>

%K nonn

%O 1,12

%A _R. H. Hardin_, connection of formula with combinatoric problem via _N. J. A. Sloane_ in the Sequence Fans Mailing List, Jun 02 2013