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A218419 Hilltop maps: number of n X n binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 n X n array.

%I A218419 #8 Jul 22 2025 23:56:28
%S A218419 1,13,357,41515,19003811,34328798853,245489633250861,
%T A218419 6942897327251230265,776657742366634012014603,
%U A218419 343639983448734808976866431015,601395784904377113605427806277106571
%N A218419 Hilltop maps: number of n X n binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..1 n X n array.
%C A218419 Diagonal of A218426
%H A218419 R. H. Hardin, <a href="/A218419/b218419.txt">Table of n, a(n) for n = 1..12</a>
%e A218419 Some solutions for n=3
%e A218419 ..1..1..1....1..1..0....1..1..1....0..0..0....0..1..1....1..1..0....0..1..0
%e A218419 ..0..1..1....0..1..0....1..1..1....1..1..0....0..1..1....1..0..1....1..0..0
%e A218419 ..1..0..1....0..1..1....0..1..1....1..1..0....0..0..1....0..0..0....1..1..1
%K A218419 nonn
%O A218419 1,2
%A A218419 _R. H. Hardin_ Oct 28 2012