A203367 Number of nX4 0..2 arrays with every 1 immediately preceded by 0 to the left or above, and every 2 immediately preceded by both a 1 and a 0

5, 110, 1570, 25087, 386353, 6026844, 93584344, 1455532600, 22625213338, 351763016010, 5468615210324, 85018833730862, 1321749696997658, 20548711257400038, 319462221618691775, 4966547386437381855

Offset

1,1

Comments

Column 4 of A203371

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +120*a(n-2) +573*a(n-3) +1592*a(n-4) +1984*a(n-5) -149*a(n-6) -4874*a(n-7) -6407*a(n-8) +5949*a(n-9) +17221*a(n-10) -31639*a(n-11) +19681*a(n-12) -10104*a(n-13) +3649*a(n-14) +2588*a(n-15) -124*a(n-16) -408*a(n-17) +112*a(n-18) -32*a(n-19)

Example

Some solutions for n=4
..0..0..0..0....0..0..0..1....0..0..1..0....0..0..0..1....0..0..0..1
..0..1..2..0....1..1..0..1....0..1..0..0....0..1..0..2....1..1..1..0
..1..0..0..0....0..2..1..0....1..0..1..0....0..0..0..0....0..1..0..0
..0..1..1..2....1..0..0..0....0..1..0..0....1..0..1..2....0..0..0..0

Crossrefs

Sequence in context: A265082 A215786 A053133 * A322631 A294965 A219161

Adjacent sequences: A203364 A203365 A203366 * A203368 A203369 A203370

Keyword

nonn

Author

R. H. Hardin Dec 31 2011

Status

approved