A260278 Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00001011.

46, 85, 230, 525, 1150, 2726, 6351, 14393, 33241, 77098, 177043, 407486, 941020, 2167955, 4992417, 11510489, 26530166, 61125209, 140873214, 324678646, 748199483, 1724247325, 3973747017, 9157675382, 21104202919, 48636225966

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 7*a(n-3) + a(n-4) + a(n-5) - 7*a(n-6) - 4*a(n-7) + 3*a(n-9) for n>12.

Empirical g.f.: x*(46 + 39*x + 145*x^2 - 27*x^3 - 16*x^4 - 165*x^5 - 43*x^6 + 16*x^7 + 41*x^8 - 19*x^9 + 12*x^10 + 4*x^11) / ((1 + x^2 - x^3)*(1 - x - x^2 - 5*x^3 - x^4 + 3*x^5 + 3*x^6)). - Colin Barker, Dec 28 2018

Example

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

Crossrefs

Column 2 of A260284.

Sequence in context: A188598 A363049 A057454 * A234260 A211330 A121929

Adjacent sequences: A260275 A260276 A260277 * A260279 A260280 A260281

Keyword

nonn

Author

R. H. Hardin, Jul 22 2015

Status

approved