cp's OEIS Frontend

A231658 Number of nX3 0..2 arrays with no element less than a strict majority of its horizontal, vertical and antidiagonal neighbors.

%I A231658 #6 Jul 23 2025 06:36:51
%S A231658 9,93,1197,13434,144465,1607589,17962078,199451319,2215334132,
%T A231658 24630393761,273787728195,3042987314978,33822943262208,
%U A231658 375948173660383,4178682035747595,46446248901585653,516253337817244309
%N A231658 Number of nX3 0..2 arrays with no element less than a strict majority of its horizontal, vertical and antidiagonal neighbors.
%C A231658 Column 3 of A231663
%H A231658 R. H. Hardin, <a href="/A231658/b231658.txt">Table of n, a(n) for n = 1..210</a>
%F A231658 Empirical: a(n) = 22*a(n-1) -187*a(n-2) +1087*a(n-3) -5320*a(n-4) +19314*a(n-5) -48040*a(n-6) +59172*a(n-7) +63954*a(n-8) -540406*a(n-9) +1405698*a(n-10) -3249182*a(n-11) +6903927*a(n-12) -2526040*a(n-13) -10496366*a(n-14) -2177417*a(n-15) +34815192*a(n-16) -61109845*a(n-17) +118442561*a(n-18) -1919557*a(n-19) -412868015*a(n-20) +741502962*a(n-21) -1238756535*a(n-22) +1796964457*a(n-23) -1329779415*a(n-24) +260960844*a(n-25) +531253784*a(n-26) -1824042081*a(n-27) +3351472259*a(n-28) -2252500439*a(n-29) +1457224992*a(n-30) -937992344*a(n-31) -796856097*a(n-32) +1654523544*a(n-33) -1270928793*a(n-34) +779543513*a(n-35) -885493704*a(n-36) +346377936*a(n-37) +423931249*a(n-38) -101753248*a(n-39) +87239521*a(n-40) -277055497*a(n-41) +214365724*a(n-42) +93299496*a(n-43) -100406405*a(n-44) -66979600*a(n-45) -442294*a(n-46) +43755691*a(n-47) -14512622*a(n-48) -17608691*a(n-49) +4308011*a(n-50) +5162569*a(n-51) +1374874*a(n-52) -853220*a(n-53) -293040*a(n-54) +48896*a(n-55) -5280*a(n-56) -2304*a(n-57)
%e A231658 Some solutions for n=5
%e A231658 ..0..0..0....0..0..2....0..0..2....0..0..0....0..2..2....0..0..1....1..0..0
%e A231658 ..1..1..0....0..0..0....2..0..0....1..1..0....0..0..0....0..2..1....0..0..2
%e A231658 ..1..0..0....2..0..0....2..0..1....1..0..0....0..2..0....1..1..2....1..0..1
%e A231658 ..1..0..0....1..0..0....2..0..2....0..0..0....2..0..0....1..1..1....0..0..1
%e A231658 ..2..1..1....1..1..2....0..0..0....2..1..0....2..0..0....2..2..1....2..0..0
%K A231658 nonn
%O A231658 1,1
%A A231658 _R. H. Hardin_, Nov 12 2013