A260468 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00010101.

34, 49, 103, 205, 414, 840, 1716, 3477, 7049, 14293, 29064, 58992, 119714, 243113, 493739, 1002385, 2035086, 4131940, 8389884, 17034549, 34585457, 70222293, 142579896, 289489424, 587771042, 1193399465, 2423058571, 4919726081

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 3*a(n-3) + a(n-4) + 2*a(n-5) + 12*a(n-8) - 4*a(n-9) - 4*a(n-11) - 4*a(n-12) for n>13.

Empirical g.f.: x*(34 + 15*x + 54*x^2 + 28*x^4 + 60*x^6 + 108*x^7 - 180*x^8 - 24*x^9 - 96*x^10 - 40*x^11 + 24*x^12) / (1 - x - 3*x^3 - x^4 - 2*x^5 - 12*x^8 + 4*x^9 + 4*x^11 + 4*x^12). - Colin Barker, Dec 29 2018

Example

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

Crossrefs

Column 1 of A260475.

Sequence in context: A370657 A260475 A107355 * A051991 A214473 A332530

Adjacent sequences: A260465 A260466 A260467 * A260469 A260470 A260471

Keyword

nonn

Author

R. H. Hardin, Jul 26 2015

Status

approved