%I #4 Mar 28 2018 10:58:11
%S 21,154,823,5463,33853,223869,1454613,9620565,63336647,419113710,
%T 2770472419,18336620495,121358670826,803332031961,5318434541385,
%U 35208666237989,233111781026276,1543314708909090,10218090869079319
%N Number of nX7 0..1 arrays with every element equal to 0, 1 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.
%C Column 7 of A301884.
%H R. H. Hardin, <a href="/A301883/b301883.txt">Table of n, a(n) for n = 1..210</a>
%H R. H. Hardin, <a href="/A301883/a301883.txt">Empirical recurrence of order 52</a>
%F Empirical recurrence of order 52 (see link above)
%e Some solutions for n=5
%e ..0..1..0..1..0..0..0. .0..1..0..1..0..1..1. .0..0..0..1..0..0..0
%e ..0..1..0..1..0..1..0. .0..1..0..1..0..0..0. .0..1..1..1..0..1..1
%e ..0..0..0..1..0..1..0. .0..1..0..1..0..1..0. .0..0..0..1..0..0..0
%e ..1..1..1..1..0..1..1. .0..0..0..1..0..1..0. .0..1..0..1..0..1..0
%e ..1..0..0..1..0..0..1. .1..1..0..0..0..1..0. .0..1..0..1..0..1..1
%Y Cf. A301884.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 28 2018