A207265 Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically.

9, 81, 217, 611, 1910, 5132, 13067, 33937, 86899, 218763, 551672, 1390836, 3491934, 8760137, 21976254, 55062713, 137841712, 344913621, 862466304, 2155128256, 5382374565, 13435295369, 33519373349, 83589288631, 208367881512

Offset

1,1

Comments

Column 4 of A207269.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 7*a(n-1) -20*a(n-2) +48*a(n-3) -132*a(n-4) +259*a(n-5) -410*a(n-6) +790*a(n-7) -1191*a(n-8) +1369*a(n-9) -2166*a(n-10) +2658*a(n-11) -2175*a(n-12) +3264*a(n-13) -3430*a(n-14) +1780*a(n-15) -3185*a(n-16) +3012*a(n-17) -722*a(n-18) +2246*a(n-19) -1944*a(n-20) -13*a(n-21) -1068*a(n-22) +856*a(n-23) +180*a(n-24) +292*a(n-25) -248*a(n-26) -56*a(n-27) -48*a(n-28) +48*a(n-29) for n>31.

Example

Some solutions for n=4
..0..1..0..1....0..1..0..0....1..1..0..1....0..0..1..0....0..1..0..1
..0..1..0..0....0..1..0..0....0..1..0..1....1..1..1..0....1..1..0..1
..1..1..0..0....0..0..1..0....0..1..0..1....0..0..1..0....0..1..0..1
..0..1..0..1....1..0..0..1....0..0..1..0....0..0..1..0....0..0..1..0

Crossrefs

Cf. A207269.

Sequence in context: A207764 A207662 A207484 * A208003 A207881 A207565

Adjacent sequences: A207262 A207263 A207264 * A207266 A207267 A207268

Keyword

nonn

Author

R. H. Hardin Feb 16 2012

Status

approved