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%I #8 Jan 08 2019 08:19:43
%S 1,1,3,6,12,24,46,91,177,349,684,1345,2640,5185,10180,19989,39249,
%T 77067,151326,297136,583444,1145622,2249491,4416993,8673001,17029896,
%U 33439105,65659456,128925825,253152696,497078745,976040481,1916507251,3763163638
%N Number of (1+1) X (n+1) arrays of permutations of 0..n*2+1 with each element having directed index change -1,1 0,-1 0,1 or 1,0.
%H R. H. Hardin, <a href="/A264507/b264507.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) + a(n-2) - 3*a(n-3) + a(n-4) + 2*a(n-5) - a(n-6).
%F Empirical g.f.: x*(1 - x + 2*x^3 - x^4) / (1 - 2*x - x^2 + 3*x^3 - x^4 - 2*x^5 + x^6). - _Colin Barker_, Jan 08 2019
%e Some solutions for n=4:
%e ..1..2..3..7..8....1..5..3..2..8....1..5..6..2..3....1..5..6..4..3
%e ..0..5..6..9..4....0..7..6..9..4....0..7..8..9..4....0..7..2..9..8
%Y Row 1 of A264506.
%K nonn
%O 1,3
%A _R. H. Hardin_, Nov 15 2015
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