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A281804 Number of 3Xn 0..1 arrays with no element unequal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%I A281804 #4 Jan 30 2017 10:43:25
%S A281804 0,9,75,372,1725,7293,29665,116539,442210,1649985,6023148,21692828,
%T A281804 77107557,271088870,944377886,3262534584,11190762816,38140286571,
%U A281804 129245999168,435739937780,1462231704463,4886245700669,16265366134625
%N A281804 Number of 3Xn 0..1 arrays with no element unequal to a strict majority of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
%C A281804 Row 3 of A281802.
%H A281804 R. H. Hardin, <a href="/A281804/b281804.txt">Table of n, a(n) for n = 1..210</a>
%F A281804 Empirical: a(n) = 9*a(n-1) -3*a(n-2) -165*a(n-3) +174*a(n-4) +1857*a(n-5) -1933*a(n-6) -15003*a(n-7) +11664*a(n-8) +91286*a(n-9) -42282*a(n-10) -427488*a(n-11) +80567*a(n-12) +1573155*a(n-13) +37911*a(n-14) -4670352*a(n-15) -843348*a(n-16) +11478699*a(n-17) +3372685*a(n-18) -23861544*a(n-19) -8964180*a(n-20) +42660411*a(n-21) +18538695*a(n-22) -66430137*a(n-23) -31623950*a(n-24) +90929253*a(n-25) +45829935*a(n-26) -110111412*a(n-27) -57390339*a(n-28) +118455852*a(n-29) +62728989*a(n-30) -113449548*a(n-31) -60198156*a(n-32) +96763954*a(n-33) +50864487*a(n-34) -73397949*a(n-35) -37857341*a(n-36) +49356480*a(n-37) +24779649*a(n-38) -29276919*a(n-39) -14214696*a(n-40) +15212211*a(n-41) +7107536*a(n-42) -6860061*a(n-43) -3073962*a(n-44) +2652939*a(n-45) +1137840*a(n-46) -866208*a(n-47) -355300*a(n-48) +233904*a(n-49) +91755*a(n-50) -50774*a(n-51) -19062*a(n-52) +8502*a(n-53) +3061*a(n-54) -1029*a(n-55) -357*a(n-56) +80*a(n-57) +27*a(n-58) -3*a(n-59) -a(n-60)
%e A281804 Some solutions for n=4
%e A281804 ..0..0..0..0. .0..0..1..0. .0..1..1..1. .0..0..0..1. .0..0..0..1
%e A281804 ..1..0..1..1. .1..1..0..1. .1..1..0..1. .1..1..1..1. .1..1..1..0
%e A281804 ..1..1..1..1. .1..0..0..0. .1..1..1..0. .0..1..1..1. .0..1..0..0
%Y A281804 Cf. A281802.
%K A281804 nonn
%O A281804 1,2
%A A281804 _R. H. Hardin_, Jan 30 2017