A218639 - OEIS

%I #4 Nov 03 2012 19:00:43

%S 1,251,4087,65523,1048363,16773477,268375113,4294000777,68704008397,

%T 1099264075379,17588224239783,281411572315259,4502584908606667,

%U 72041354562688477,1152661609402891673,18442584732844711745

%N Hilltop maps: number of 4Xn binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 4Xn array

%C Row 4 of A218638

%H R. H. Hardin, <a href="/A218639/b218639.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 15*a(n-1) +14*a(n-2) +30*a(n-3) +27*a(n-4) +73*a(n-5) +96*a(n-6) +230*a(n-7) +167*a(n-8) -69*a(n-9) -116*a(n-10) -60*a(n-11) -13*a(n-12) -95*a(n-13) -254*a(n-14) -292*a(n-15) -120*a(n-16) for n>17

%e Some solutions for n=3

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

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Nov 03 2012