cp's OEIS Frontend

A221330 Number of 3Xn arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.

%I A221330 #6 Jun 02 2025 08:16:34
%S A221330 1,99,2008,46105,1010078,22181855,487335857,10702699654,234960268184,
%T A221330 5156938918020,113169823744104,2483341620801750,54490904644158524,
%U A221330 1195642566518402694,26234513648153012228,575627427381833999655
%N A221330 Number of 3Xn arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2.
%C A221330 Row 3 of A221328
%H A221330 R. H. Hardin, <a href="/A221330/b221330.txt">Table of n, a(n) for n = 1..155</a>
%F A221330 Empirical: a(n) = 41*a(n-1) -510*a(n-2) +2064*a(n-3) -290*a(n-4) -18526*a(n-5) +25526*a(n-6) +24962*a(n-7) -5089*a(n-8) +307825*a(n-9) +251112*a(n-10) +475211*a(n-11) +1516807*a(n-12) +939017*a(n-13) +282103*a(n-14) -33095*a(n-15) -762290*a(n-16) +335187*a(n-17) +743367*a(n-18) -337130*a(n-19) -221548*a(n-20) +169223*a(n-21) +5398*a(n-22) -47623*a(n-23) +5009*a(n-24) +6337*a(n-25) -804*a(n-26) -272*a(n-27) +20*a(n-28) +4*a(n-29) for n>30
%e A221330 Some solutions for n=3
%e A221330 ..1..1..1....1..0..0....1..2..0....0..2..1....0..1..2....1..1..1....1..1..1
%e A221330 ..2..0..2....2..2..1....2..1..0....0..1..2....2..2..1....2..2..0....1..0..2
%e A221330 ..0..1..1....0..2..1....2..0..1....0..2..1....0..1..0....0..1..1....2..1..0
%K A221330 nonn
%O A221330 1,2
%A A221330 _R. H. Hardin_ Jan 11 2013