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%I #4 Feb 28 2015 11:36:32
%S 1647,4248,11386,30816,83325,225253,602886,1605726,4293918,11529741,
%T 30959919,83094838,222919389,597525981,1601258653,4293585291,
%U 11516774865,30888797609,82837467594,222143245920,595677211881,1597318079838
%N Number of length n+6 0..2 arrays with at most two downsteps in every 6 consecutive neighbor pairs
%C Column 6 of A255622
%H R. H. Hardin, <a href="/A255620/b255620.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) -3*a(n-2) +8*a(n-3) -9*a(n-4) +3*a(n-5) +46*a(n-6) -69*a(n-7) +27*a(n-8) -329*a(n-9) +354*a(n-10) -6*a(n-11) -395*a(n-12) +585*a(n-13) -216*a(n-14) +2590*a(n-15) -3837*a(n-16) +1548*a(n-17) -370*a(n-18) -69*a(n-19) -36*a(n-20)
%e Some solutions for n=4
%e ..1....1....0....2....1....1....1....1....0....0....1....1....1....2....2....0
%e ..1....2....0....0....1....2....0....2....1....0....0....2....1....2....1....1
%e ..2....0....1....0....2....0....0....2....0....2....1....0....2....2....0....2
%e ..0....0....1....0....2....1....1....1....2....2....1....0....2....2....1....0
%e ..0....0....1....2....2....2....0....2....0....2....2....0....2....1....2....0
%e ..1....0....1....2....2....0....1....2....1....0....0....0....0....1....2....1
%e ..1....0....0....0....1....0....1....0....1....2....2....2....0....2....2....2
%e ..0....0....2....0....1....0....2....0....2....0....2....0....0....1....2....1
%e ..0....1....2....1....1....1....0....2....0....0....2....2....2....2....2....1
%e ..0....2....2....2....0....1....0....1....0....0....0....0....2....2....1....0
%Y Cf. A255622
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 28 2015
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