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A220372 Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and vertical neighbors in a random 0..2 nX2 array 4

%I

%S 1,6,23,94,380,1494,5939,23398,92317,363370,1430190,5625584,22124617,

%T 86997410,342060007,1344843036,5287206382,20786010360,81716574499,

%U 321251714484,1262927656331,4964894997840,19518245673568,76731015101962

%N Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and vertical neighbors in a random 0..2 nX2 array

%C Column 2 of A220375

%H R. H. Hardin, <a href="/A220372/b220372.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) -21*a(n-2) +23*a(n-3) -17*a(n-4) +11*a(n-5) +55*a(n-6) -199*a(n-7) +241*a(n-8) -157*a(n-9) -14*a(n-10) +217*a(n-11) -546*a(n-12) +850*a(n-13) -927*a(n-14) +254*a(n-15) +555*a(n-16) -375*a(n-17) +150*a(n-18) +848*a(n-19) +368*a(n-20) +998*a(n-21) +666*a(n-22) +1091*a(n-23) +2744*a(n-24) +1499*a(n-25) +3393*a(n-26) +1420*a(n-27) +3704*a(n-28) -272*a(n-29) +3190*a(n-30) -1290*a(n-31) +1774*a(n-32) -418*a(n-33) +486*a(n-34) -72*a(n-35) +68*a(n-36) -8*a(n-37)

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 13 2012

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Last modified May 24 04:32 EDT 2022. Contains 354005 sequences. (Running on oeis4.)