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%I #4 Dec 21 2012 06:18:23
%S 1,6,19,76,267,1074,4069,15916,62161,243418,954189,3745072,14698115,
%T 57707746,226582983,889710492,3493659533,13718948094,53871964175,
%U 211547211964,830715606031,3262105325370,12809842147609,50302517147348
%N Equals two maps: number of 2Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 2Xn array
%C Row 2 of A220794
%H R. H. Hardin, <a href="/A220795/b220795.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) +10*a(n-2) -34*a(n-3) -66*a(n-4) +98*a(n-5) +320*a(n-6) -66*a(n-7) -916*a(n-8) -306*a(n-9) +1454*a(n-10) +1054*a(n-11) -1038*a(n-12) -1690*a(n-13) -376*a(n-14) +1514*a(n-15) +1301*a(n-16) -1114*a(n-17) -1008*a(n-18) +796*a(n-19) -568*a(n-20) -624*a(n-21) +720*a(n-22) -144*a(n-23) +64*a(n-24) +64*a(n-25)
%e Some solutions for n=3
%e ..1..0..0....0..1..1....1..0..1....0..1..0....0..0..1....1..0..1....0..1..1
%e ..0..0..0....0..1..1....1..0..1....0..0..0....1..0..1....1..0..0....1..1..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Dec 21 2012
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