A177298 - OEIS

%I #18 May 16 2020 01:33:32

%S 1,1,70,780,11482,135040,1543862,16699380,175280570,1792874048,

%T 17990831182,177773616180,1735220375914,16769137076968,

%U 160740670148270,1530462874512756,14491157235576770,136575590461035368,1282229192334549022,11999276440029403356,111987255233226452770

%N Number of permutations of 4 copies of 1..n with all adjacent differences <= 1 in absolute value.

%C a(n) = (4n)!/24^n = A014608(n) for n<=2.

%H Andrew Howroyd, <a href="/A177298/b177298.txt">Table of n, a(n) for n = 0..200</a>

%Y Cf. A014608.

%Y Column k=4 of A331562.

%K nonn

%O 0,3

%A _R. H. Hardin_, May 06 2010

%E a(0)=1 prepended by _Alois P. Heinz_, Jan 20 2020

%E a(12)-a(13) from _Alois P. Heinz_, Jan 21 2020

%E Terms a(14) and beyond from _Andrew Howroyd_, May 15 2020