%I #10 Apr 08 2021 05:43:50

%S 1,6,16,120,648,5040,38592,362880,3600000,39916800,476928000,

%T 6227020800,87127488000,1307674368000

%N Number of arrays of length n that are sums of 2 consecutive elements of length n+1 permutations of 0..n.

%C Column 2 of A229565.

%e All solutions for n=3:

%e 1 3 5 3 4 4 5 4 1 3 5 2 2 3 2 1

%e 4 5 2 2 1 3 4 5 3 1 3 1 3 4 5 2

%e 5 3 1 3 2 2 1 2 5 3 1 4 4 3 4 5

%K nonn,more

%O 1,2

%A _R. H. Hardin_, Sep 26 2013