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Number of (3+1)X(n+1) arrays of permutations of 0..n*4+3 with each element having directed index change -1,0 0,2 -1,-2 or 1,0.
1

%I #4 Nov 16 2015 17:15:27

%S 1,3,9,42,196,644,2116,6854,22201,78076,274576,937960,3204100,

%T 10890360,37015056,126620208,433139344,1480295124,5059050129,

%U 17273618712,58979036736,201463380504,688168134481,2350844113032,8030694487104

%N Number of (3+1)X(n+1) arrays of permutations of 0..n*4+3 with each element having directed index change -1,0 0,2 -1,-2 or 1,0.

%C Row 3 of A264520.

%H R. H. Hardin, <a href="/A264521/b264521.txt">Table of n, a(n) for n = 1..210</a>

%e Some solutions for n=4

%e ..5..6..9..1..2....7..6..0..1..2....7..8..0..1..9....5..6..7..1..2

%e ..0.13.14..3..4...12.13.14..3..4...12.13..2..3..4....0.13.12..3..4

%e .15.18..7..8.19....5.18.19..8..9....5..6.17.18.19...17.18.19..8..9

%e .10.11.12.16.17...10.11.15.16.17...10.11.15.16.14...10.11.15.16.14

%Y Cf. A264520.

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 16 2015