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Number of nX4 0..2 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
1

%I #4 Dec 29 2016 04:02:16

%S 6,92,886,7048,49328,320755,2001079,12072893,71202942,412532945,

%T 2356359770,13301182445,74334613125,411868280767,2265028406966,

%U 12374632703132,67213554157525,363176806160897,1953185818717956

%N Number of nX4 0..2 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%C Column 4 of A280217.

%H R. H. Hardin, <a href="/A280214/b280214.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 9*a(n-1) +24*a(n-2) -348*a(n-3) -228*a(n-4) +5697*a(n-5) +2765*a(n-6) -50268*a(n-7) -51060*a(n-8) +250840*a(n-9) +591864*a(n-10) -585360*a(n-11) -3858303*a(n-12) -1137624*a(n-13) +14149674*a(n-14) +17398900*a(n-15) -25090194*a(n-16) -84223551*a(n-17) -8655442*a(n-18) +220307862*a(n-19) +178052856*a(n-20) -257194705*a(n-21) -571042194*a(n-22) -93277806*a(n-23) +966901009*a(n-24) +606464421*a(n-25) -478771590*a(n-26) -631840507*a(n-27) -1140621168*a(n-28) +221715324*a(n-29) +1795176848*a(n-30) +96657456*a(n-31) -215494272*a(n-32) -332769984*a(n-33) -1047978240*a(n-34) +427905024*a(n-35) +449986560*a(n-36) -124551168*a(n-37) +191496192*a(n-38) -153092096*a(n-39) -88080384*a(n-40) +88080384*a(n-41) -16777216*a(n-42) for n>51

%e Some solutions for n=4

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

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

%e ..0..1..1..2. .0..2..2..0. .0..0..2..2. .0..1..0..0. .1..0..1..1

%e ..1..0..2..2. .0..0..0..0. .2..2..2..2. .0..0..0..0. .0..0..0..1

%Y Cf. A280217.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 29 2016