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A264491 Number of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having directed index change 2,-1 1,0 2,1 0,-1 -2,-2 or -1,0.

%I A264491 #10 Jan 08 2019 06:45:23
%S A264491 3,1,10,8,35,42,130,194,501,849,1979,3613,7942,15145,32182,62953,
%T A264491 131165,260426,536438,1074379,2198378,4425274,9019904,18210519,
%U A264491 37034259,74898261,152118445,307953916,624975597,1265962640,2568054807,5203674585
%N A264491 Number of (2+1) X (n+1) arrays of permutations of 0..n*3+2 with each element having directed index change 2,-1 1,0 2,1 0,-1 -2,-2 or -1,0.
%H A264491 R. H. Hardin, <a href="/A264491/b264491.txt">Table of n, a(n) for n = 1..210</a>
%F A264491 Empirical: a(n) = 3*a(n-2) + 2*a(n-3) + a(n-4) - a(n-5).
%F A264491 Empirical g.f.: x*(3 + x + x^2 - x^3) / (1 - 3*x^2 - 2*x^3 - x^4 + x^5). - _Colin Barker_, Jan 08 2019
%e A264491 Some solutions for n=4:
%e A264491 .12..6..7..4..9....5..6.14..8..9...12..6..7..8..9....5..6.14..8..9
%e A264491 .10.11..2.13.14...10.11.12.13..4...10.11..2.13..4...10..7.12.13..4
%e A264491 ..5..0..1..8..3....1..0..7..2..3....5..0..1.14..3...11..0..1..2..3
%Y A264491 Row 2 of A264490.
%K A264491 nonn
%O A264491 1,1
%A A264491 _R. H. Hardin_, Nov 14 2015