A261285 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00010101 or 01010101.

36, 50, 96, 166, 307, 540, 1015, 1786, 3304, 5862, 10877, 19316, 35609, 63526, 116992, 209094, 383787, 687684, 1260543, 2262114, 4138240, 7439142, 13591813, 24462924, 44638225, 80433102, 146628424, 264446262, 481653251, 869371260, 1582318631

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-2) + 2*a(n-3) + 4*a(n-4) + 3*a(n-6) - 8*a(n-7) + 9*a(n-8) - 6*a(n-9) - 4*a(n-10) - 4*a(n-11) - 4*a(n-12) for n>13.

Empirical g.f.: x*(36 + 50*x + 60*x^2 + 44*x^3 - 33*x^4 - 18*x^5 - 116*x^6 + 106*x^7 - 231*x^8 - 78*x^9 - 72*x^10 - 36*x^11 + 28*x^12) / (1 - x^2 - 2*x^3 - 4*x^4 - 3*x^6 + 8*x^7 - 9*x^8 + 6*x^9 + 4*x^10 + 4*x^11 + 4*x^12). - Colin Barker, Dec 30 2018

Example

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

Crossrefs

Column 1 of A261292.

Sequence in context: A332287 A050691 A211720 * A261257 A188243 A335104

Adjacent sequences: A261282 A261283 A261284 * A261286 A261287 A261288

Keyword

nonn

Author

R. H. Hardin, Aug 14 2015

Status

approved