A260363 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001111.

48, 78, 208, 436, 616, 1378, 2880, 4904, 9776, 19458, 35928, 70096, 136184, 257558, 498984, 963740, 1839600, 3547926, 6837184, 13109580, 25236616, 48572826, 93304016, 179507232, 345319152, 663776330, 1276734024, 2455611208, 4721490968

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) - a(n-2) + 5*a(n-3) - a(n-4) + 5*a(n-5) - 3*a(n-6) - a(n-7).

Empirical g.f.: 2*x*(24 + 15*x + 89*x^2 + 33*x^3 + 23*x^4 - 2*x^5 - 50*x^6) / (1 - x + x^2 - 5*x^3 + x^4 - 5*x^5 + 3*x^6 + x^7). - Colin Barker, Dec 29 2018

Example

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

Crossrefs

Column 1 of A260370.

Sequence in context: A261709 A261704 A260370 * A261553 A335281 A335196

Adjacent sequences: A260360 A260361 A260362 * A260364 A260365 A260366

Keyword

nonn

Author

R. H. Hardin, Jul 23 2015

Status

approved