A240651 Number of nX3 0..1 arrays with no element equal to exactly one horizontal or vertical neighbor, with new values 0..1 introduced in row major order

1, 2, 9, 17, 43, 136, 402, 1180, 3518, 10525, 31454, 94059, 281484, 842574, 2522415, 7552239, 22613578, 67714627, 202772197, 607215863, 1818375168, 5445371326, 16306993036, 48833947510, 146241553581, 437945846008, 1311506541151

Offset

1,2

Comments

Column 3 of A240656

Links

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

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) +2*a(n-3) -11*a(n-4) -12*a(n-5) -9*a(n-6) +15*a(n-7) +23*a(n-8) +20*a(n-9) -6*a(n-10) -15*a(n-11) -12*a(n-12) -2*a(n-13) +3*a(n-14) +a(n-15)

Example

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

Crossrefs

Sequence in context: A100291 A126082 A083707 * A357432 A369000 A346102

Adjacent sequences: A240648 A240649 A240650 * A240652 A240653 A240654

Keyword

nonn

Author

R. H. Hardin, Apr 09 2014

Status

approved