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

%I #4 Nov 11 2015 19:44:17

%S 8,55,490,3567,28925,223356,1759250,13750304,107777857,843913133,

%T 6610346674,51772001513,405494413096,3175909815583,24874462255642,

%U 194822212724279,1525890963999701,11951115491689468,93603785927597586

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

%C Row 2 of A264341.

%H R. H. Hardin, <a href="/A264342/b264342.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) +26*a(n-2) -72*a(n-3) -195*a(n-4) +284*a(n-5) +555*a(n-6) -424*a(n-7) -555*a(n-8) +284*a(n-9) +195*a(n-10) -72*a(n-11) -26*a(n-12) +6*a(n-13) +a(n-14)

%e Some solutions for n=4

%e ..0..8..9..4..3....0..2..1..4..3....0..8..1..4..3....0..8..3..2..4

%e ..6..5.14..1..2....6..5.14..9..8....6..5.14..9..2....6..5..7..1..9

%e .10.11.13.12..7...10.11.13.12..7...10.12.11.13..7...10.11.13.12.14

%Y Cf. A264341.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 11 2015