%I #4 Nov 23 2017 09:24:31

%S 7,87,774,7071,64189,588529,5400933,49414072,452274232,4141178883,

%T 37915462501,347125927592,3178043159907,29096212160166,

%U 266386963989786,2438870587989546,22328758454009391,204428063085791198

%N Number of nX4 0..1 arrays with each 1 horizontally or vertically adjacent to 1, 2 or 4 1s.

%C Column 4 of A295531.

%H R. H. Hardin, <a href="/A295527/b295527.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) +13*a(n-2) +115*a(n-3) +249*a(n-4) +426*a(n-5) -1288*a(n-6) -1624*a(n-7) +5590*a(n-8) +6289*a(n-9) -7886*a(n-10) -8123*a(n-11) +5854*a(n-12) +3323*a(n-13) -13470*a(n-14) -5787*a(n-15) +8339*a(n-16) -8574*a(n-17) -31382*a(n-18) -19075*a(n-19) +1988*a(n-20) +11913*a(n-21) -2666*a(n-22) +8280*a(n-23) +11515*a(n-24) +16869*a(n-25) +5768*a(n-26) -4269*a(n-27) -10768*a(n-28) -4992*a(n-29) +1675*a(n-30) +2329*a(n-31) +1426*a(n-32) -22*a(n-33) +215*a(n-34) +a(n-35) -79*a(n-36) -387*a(n-37) -93*a(n-38) +30*a(n-39) +31*a(n-40) +8*a(n-41) -8*a(n-42) -3*a(n-43) +a(n-45)

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A295531.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 23 2017