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A303521 Number of nX4 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

%I A303521 #4 Apr 25 2018 12:38:20
%S A303521 5,21,37,103,340,1115,4112,16640,71025,320957,1510853,7287031,
%T A303521 35723065,176869202,880763327,4401181230,22037652351,110478062574,
%U A303521 554227859714,2781487076749,13962670138510,70100301160570,351970530142109
%N A303521 Number of nX4 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
%C A303521 Column 4 of A303525.
%H A303521 R. H. Hardin, <a href="/A303521/b303521.txt">Table of n, a(n) for n = 1..210</a>
%F A303521 Empirical: a(n) = 7*a(n-1) -9*a(n-2) +8*a(n-3) -68*a(n-4) +8*a(n-5) -6*a(n-6) +260*a(n-7) +444*a(n-8) +617*a(n-9) -488*a(n-10) -858*a(n-11) -2426*a(n-12) -1778*a(n-13) -2233*a(n-14) +1090*a(n-15) +2944*a(n-16) +5714*a(n-17) +4242*a(n-18) +1676*a(n-19) -5030*a(n-20) -6560*a(n-21) -3203*a(n-22) +5344*a(n-23) +11678*a(n-24) +10874*a(n-25) +8003*a(n-26) -6178*a(n-27) -11743*a(n-28) -18221*a(n-29) -11933*a(n-30) -7346*a(n-31) +3388*a(n-32) +8166*a(n-33) +9709*a(n-34) +6270*a(n-35) +2172*a(n-36) -1377*a(n-37) -2343*a(n-38) -1877*a(n-39) -576*a(n-40) +51*a(n-41) +210*a(n-42) +170*a(n-43) +22*a(n-44) -13*a(n-45) -31*a(n-46) -9*a(n-47) for n>49
%e A303521 Some solutions for n=5
%e A303521 ..0..1..0..0. .0..1..1..1. .0..0..0..1. .0..1..1..0. .0..1..1..0
%e A303521 ..0..0..1..0. .0..1..0..1. .0..1..1..1. .0..1..0..1. .1..0..1..0
%e A303521 ..1..1..1..1. .0..1..0..1. .0..1..0..1. .0..1..0..1. .1..0..1..0
%e A303521 ..1..0..1..1. .0..1..1..1. .0..0..0..1. .0..1..0..1. .1..0..1..0
%e A303521 ..1..0..1..0. .0..1..0..0. .0..1..0..1. .0..1..0..1. .1..0..1..0
%Y A303521 Cf. A303525.
%K A303521 nonn
%O A303521 1,1
%A A303521 _R. H. Hardin_, Apr 25 2018