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Number of length n+5 0..3 arrays with at most one downstep in every 5 consecutive neighbor pairs
1

%I #4 Jun 08 2015 11:50:34

%S 1212,2936,7834,21860,59188,149960,370510,941024,2487276,6650600,

%T 17371025,44270908,112541478,290771496,762899717,1998910152,

%U 5175319416,13289503784,34202437664,88756842476,231356200114,601422231744

%N Number of length n+5 0..3 arrays with at most one downstep in every 5 consecutive neighbor pairs

%C Column 5 of A258730

%H R. H. Hardin, <a href="/A258727/b258727.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4) +52*a(n-5) -128*a(n-6) +108*a(n-7) -31*a(n-8) -68*a(n-10) +92*a(n-11) -31*a(n-12) +4*a(n-15) -a(n-16)

%e Some solutions for n=4

%e ..0....1....1....0....1....0....1....3....3....2....1....1....1....3....3....1

%e ..2....3....2....3....0....1....0....3....0....2....1....3....1....0....0....1

%e ..0....0....0....3....2....3....0....3....0....2....0....0....1....0....0....2

%e ..0....0....1....3....2....0....1....3....0....2....0....0....1....1....1....3

%e ..0....1....1....0....3....0....1....1....0....2....1....1....0....3....1....1

%e ..0....2....1....1....3....1....2....1....3....3....2....1....2....3....1....1

%e ..2....3....3....1....0....2....0....2....1....0....3....3....2....0....1....1

%e ..3....1....0....2....2....2....0....2....1....2....1....1....2....1....1....3

%e ..0....1....3....3....2....3....2....2....3....3....1....1....3....2....3....3

%Y Cf. A258730

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 08 2015