A204374 Number of (n+2)X3 0..1 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..1 introduced in row major order

33, 51, 78, 113, 182, 286, 439, 710, 1128, 1775, 2873, 4628, 7422, 12063, 19589, 31772, 51859, 84665, 138190, 226233, 370522, 606890, 995484, 1633475, 2680738, 4402540, 7231998, 11881418, 19526806, 32096793, 52763245, 86751961, 142648787

Offset

1,1

Comments

Column 1 of A204381

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -2*a(n-2) -2*a(n-4) +2*a(n-5) +3*a(n-6) -6*a(n-7) +3*a(n-8) -a(n-11) +2*a(n-12) -a(n-13) -a(n-14) +2*a(n-15) -a(n-16)

Example

Some solutions for n=3
..0..0..1....0..1..0....0..0..1....0..0..0....0..1..1....0..0..0....0..0..1
..0..0..0....0..1..0....1..0..1....0..0..0....1..1..1....0..0..0....1..1..1
..0..1..0....0..1..0....0..0..0....0..1..1....0..1..1....1..1..1....1..1..1
..0..1..0....0..0..0....0..0..0....0..0..0....0..0..1....1..1..1....0..1..0
..0..0..0....1..1..0....1..0..1....0..1..0....0..0..0....0..1..0....0..1..1

Crossrefs

Sequence in context: A014976 A364286 A109407 * A261107 A211141 A007373

Adjacent sequences: A204371 A204372 A204373 * A204375 A204376 A204377

Keyword

nonn

Author

R. H. Hardin Jan 14 2012

Status

approved