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%I #5 Dec 15 2012 14:42:21
%S 1,6,27,107,461,1844,7502,29893,119342,473933,1881751,7461042,
%T 29575992,117195951,464344817,1839594735,7287640647,28869446541,
%U 114362678138,453029324891,1794595194945,7108951540013,28160738630498,111553241825416
%N Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, vertical and antidiagonal neighbors in a random 0..3 nX2 array
%C Column 2 of A220532
%H R. H. Hardin, <a href="/A220529/b220529.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) -5*a(n-2) -18*a(n-3) +24*a(n-4) -3*a(n-5) +a(n-6) -49*a(n-7) +113*a(n-8) +136*a(n-9) -407*a(n-10) +376*a(n-11) +261*a(n-12) -819*a(n-13) -157*a(n-14) +1276*a(n-15) -1095*a(n-16) -1063*a(n-17) +566*a(n-18) +423*a(n-19) -11368*a(n-20) +9391*a(n-21) -15574*a(n-22) -8963*a(n-23) +1529*a(n-24) -27108*a(n-25) +1001*a(n-26) -32699*a(n-27) -41186*a(n-28) +30586*a(n-29) -143578*a(n-30) +53047*a(n-31) -116139*a(n-32) +389*a(n-33) -37253*a(n-34) -146288*a(n-35) +52769*a(n-36) -111475*a(n-37) -122524*a(n-38) +42899*a(n-39) -163248*a(n-40) +149127*a(n-41) -118651*a(n-42) -49351*a(n-43) +76302*a(n-44) -57124*a(n-45) -7405*a(n-46) +26959*a(n-47) -45252*a(n-48) +27865*a(n-49) -8493*a(n-50) -2541*a(n-51) +10641*a(n-52) -4206*a(n-53) -595*a(n-54) +3901*a(n-55) -2258*a(n-56) +316*a(n-57) +784*a(n-58) -793*a(n-59) +318*a(n-60) -22*a(n-61) -63*a(n-62) +41*a(n-63) -18*a(n-64) +a(n-65)
%e Some solutions for n=3
%e ..1..1....0..0....0..1....0..1....1..1....1..1....0..1....0..0....0..0....0..0
%e ..0..0....1..1....0..0....1..0....1..1....0..0....0..0....0..1....0..0....1..0
%e ..0..0....1..0....1..1....0..0....1..1....1..0....1..0....1..0....1..0....1..0
%K nonn
%O 1,2
%A _R. H. Hardin_ Dec 15 2012
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