A220339 - OEIS

%I #5 Dec 11 2012 07:42:41

%S 1,5,24,89,389,1570,6413,25744,103229,412081,1643706,6548560,26080372,

%T 103836793,413362985,1645415613,6549395074,26068520679,103759005831,

%U 412983036406,1643754108417,6542452940294,26040170803581,103644625748031

%N Equals two maps: number of nX2 binary arrays indicating the locations of corresponding elements equal to exactly two of their king-move neighbors in a random 0..3 nX2 array

%C Column 2 of A220342

%H R. H. Hardin, <a href="/A220339/b220339.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) +6*a(n-2) -22*a(n-3) -15*a(n-4) +10*a(n-5) +56*a(n-6) +34*a(n-7) -68*a(n-8) -12*a(n-9) -247*a(n-10) +258*a(n-11) +429*a(n-12) -176*a(n-13) -798*a(n-14) +50*a(n-15) +1112*a(n-16) -368*a(n-17) -628*a(n-18) +288*a(n-19) -56*a(n-20) -248*a(n-21) +96*a(n-22)

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 11 2012