A207271 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically

9, 81, 193, 611, 1602, 3513, 8327, 17568, 36988, 76723, 153865, 308777, 608391, 1189918, 2313136, 4458599, 8562580, 16354499, 31118601, 59018399, 111556847, 210352934, 395641010, 742567333, 1391072247, 2601239676, 4856734666

Offset

1,1

Comments

Row 4 of A207269

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) -a(n-3) -30*a(n-4) -13*a(n-5) +54*a(n-6) +109*a(n-7) -36*a(n-8) -191*a(n-9) -186*a(n-10) +146*a(n-11) +313*a(n-12) +245*a(n-13) -177*a(n-14) -350*a(n-15) -329*a(n-16) +108*a(n-17) +320*a(n-18) +341*a(n-19) -41*a(n-20) -205*a(n-21) -228*a(n-22) -5*a(n-23) +70*a(n-24) +106*a(n-25) +23*a(n-26) -9*a(n-27) -38*a(n-28) -12*a(n-29) +9*a(n-31) +2*a(n-32) -a(n-34)

Example

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

Crossrefs

Sequence in context: A207731 A208690 A207342 * A207764 A207662 A207484

Adjacent sequences: A207268 A207269 A207270 * A207272 A207273 A207274

Keyword

nonn

Author

R. H. Hardin Feb 16 2012

Status

approved