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

1,2

Comments

Row 3 of A221328

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

Example

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

Crossrefs

Sequence in context: A305721 A197372 A174944 * A246247 A157370 A163040

Adjacent sequences: A221327 A221328 A221329 * A221331 A221332 A221333

Keyword

nonn

Author

R. H. Hardin Jan 11 2013

Status

approved