cp's OEIS Frontend

A221895 Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without move-in move-out straight through or left turns.

%I A221895 #6 Jul 23 2025 02:18:58
%S A221895 6,258,7667,235332,7197649,220361275,6744533268,206439650412,
%T A221895 6318757208626,193406107213008,5919823712888467,181195475755599060,
%U A221895 5546077402982111186,169755753751290765761,5195927470447150844696
%N A221895 Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal, vertical or antidiagonal neighbor, without move-in move-out straight through or left turns.
%C A221895 Column 3 of A221898
%H A221895 R. H. Hardin, <a href="/A221895/b221895.txt">Table of n, a(n) for n = 1..163</a>
%F A221895 Empirical: a(n) = 14*a(n-1) +401*a(n-2) +3090*a(n-3) +7741*a(n-4) -40484*a(n-5) -361940*a(n-6) -1090743*a(n-7) -1171988*a(n-8) +2002414*a(n-9) +720120*a(n-10) -7394610*a(n-11) +17527526*a(n-12) -2069693*a(n-13) -44623518*a(n-14) +78779650*a(n-15) -104778098*a(n-16) +119555094*a(n-17) +11992813*a(n-18) -174397406*a(n-19) +103166505*a(n-20) +131329969*a(n-21) -214551956*a(n-22) +84757573*a(n-23) +13317994*a(n-24) -10733620*a(n-25) +1466700*a(n-26) -21780*a(n-27) -2160*a(n-28)
%e A221895 Some solutions for n=3
%e A221895 ..0..0..0....0..1..2....1..0..2....0..1..1....3..0..2....1..0..1....0..2..0
%e A221895 ..3..1..2....0..3..0....1..1..0....0..4..2....0..3..0....3..1..0....4..0..0
%e A221895 ..1..0..2....1..2..0....2..1..1....1..0..0....0..0..1....0..0..3....0..3..0
%K A221895 nonn
%O A221895 1,1
%A A221895 _R. H. Hardin_ Jan 30 2013