A261108 Number of (n+2) X (3+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010001 00010101 or 01010101.

63, 106, 278, 566, 1408, 2902, 7284, 14942, 37432, 76838, 192624, 395390, 990928, 2034038, 5098214, 10464850, 26228746, 53838574, 134940686, 276986458, 694234628, 1425023498, 3571661670, 7331384958, 18375286712, 37718103630

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-2) + 10*a(n-4) + 5*a(n-6) + 2*a(n-8) - 2*a(n-10) + a(n-12) for n>13.

Empirical g.f.: x*(63 + 106*x + 89*x^2 + 248*x^3 - 56*x^4 + 144*x^5 - 35*x^6 + 46*x^7 - 16*x^8 - 50*x^9 + 18*x^10 + 26*x^11 - 7*x^12) / (1 - 3*x^2 - 10*x^4 - 5*x^6 - 2*x^8 + 2*x^10 - x^12). - Colin Barker, Dec 30 2018

Example

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

Crossrefs

Column 3 of A261113.

Sequence in context: A023688 A118157 A257897 * A147194 A147398 A166394

Adjacent sequences: A261105 A261106 A261107 * A261109 A261110 A261111

Keyword

nonn

Author

R. H. Hardin, Aug 08 2015

Status

approved