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.
1, 99, 2008, 46105, 1010078, 22181855, 487335857, 10702699654, 234960268184, 5156938918020, 113169823744104, 2483341620801750, 54490904644158524, 1195642566518402694, 26234513648153012228, 575627427381833999655
Offset: 1
Keywords
Examples
Some solutions for n=3 ..1..1..1....1..0..0....1..2..0....0..2..1....0..1..2....1..1..1....1..1..1 ..2..0..2....2..2..1....2..1..0....0..1..2....2..2..1....2..2..0....1..0..2 ..0..1..1....0..2..1....2..0..1....0..2..1....0..1..0....0..1..1....2..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..155
Formula
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
Comments