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%I #8 Mar 10 2018 05:46:52
%S 5,57,417,3249,25533,199489,1560161,12202673,95434773,746388537,
%T 5837454753,45654295713,357058903853,2792531543489,21840184444225,
%U 170810481722657,1335896257560101,10447946710663673,81712625405191841
%N Hilltop maps: number of n X 3 binary arrays indicating the locations of corresponding elements not exceeded by any king-move neighbor in a random 0..1 n X 3 array.
%C Column 3 of A218663.
%H R. H. Hardin, <a href="/A218658/b218658.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) + 11*a(n-2) + 26*a(n-3) - 5*a(n-4) - 5*a(n-6).
%F Empirical g.f.: x*(5 + 27*x + 20*x^2 - 10*x^3 - 5*x^4 - 5*x^5) / (1 - 6*x - 11*x^2 - 26*x^3 + 5*x^4 + 5*x^6). - _Colin Barker_, Mar 10 2018
%e Some solutions for n=3:
%e ..0..0..1....1..1..0....1..0..0....1..1..0....1..0..0....0..1..0....1..1..1
%e ..1..1..1....1..1..1....0..0..1....1..0..0....1..0..1....0..1..1....0..1..0
%e ..1..0..0....1..1..0....0..1..0....0..1..1....0..1..0....0..1..0....1..1..1
%Y Cf. A218663.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 04 2012