%I #4 Apr 10 2015 14:17:44

%S 219,402,753,1424,2693,5088,9613,18104,34013,63928,120362,226816,

%T 427341,804974,1516179,2855304,5376354,10123582,19065294,35907400,

%U 67626166,127359488,239852341,451704432,850669960,1602023036,3017039568

%N Number of length n+7 0..1 arrays with at most two downsteps in every 7 consecutive neighbor pairs

%C Column 7 of A256816

%H R. H. Hardin, <a href="/A256815/b256815.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-4) -2*a(n-5) +10*a(n-7) -7*a(n-8) -12*a(n-11) +9*a(n-12) -24*a(n-14) +18*a(n-15)

%e Some solutions for n=4

%e ..1....0....1....1....0....0....0....1....1....1....1....1....0....0....0....0

%e ..0....0....1....1....0....0....1....1....1....1....1....0....1....1....1....0

%e ..1....0....1....1....1....1....0....1....1....1....0....1....0....1....1....0

%e ..1....0....0....1....1....1....0....1....0....0....1....0....0....1....1....1

%e ..0....1....1....1....0....1....0....0....0....0....0....0....0....1....1....0

%e ..0....1....0....0....1....0....1....0....1....0....0....0....1....0....0....1

%e ..0....0....0....0....1....0....0....0....0....1....1....1....1....0....1....1

%e ..1....1....0....1....0....0....1....0....0....0....1....1....1....1....1....1

%e ..1....1....0....0....1....0....1....1....0....1....1....0....1....1....0....0

%e ..1....0....0....0....1....1....1....1....0....1....1....0....0....0....0....0

%e ..1....0....0....1....1....0....1....1....0....1....0....1....0....0....0....0

%Y Cf. A256816

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 10 2015