login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A260131 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 01010101 or 01010111. 1
36, 58, 138, 266, 472, 944, 1880, 3562, 6866, 13450, 26016, 50176, 97392, 188890, 365434, 707786, 1371848, 2657040, 5145832, 9969162, 19312130, 37406666, 72459984, 140365536, 271897664, 526684282, 1020240874, 1976299402, 3828249912 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + 3*a(n-3) + a(n-4) for n>5.
Empirical g.f.: 2*x*(18 + 11*x + 40*x^2 + 10*x^3 - 2*x^4) / (1 - x - 3*x^3 - x^4). - Colin Barker, Dec 28 2018
EXAMPLE
Some solutions for n=4:
..0..1..0....1..0..1....0..1..1....0..1..0....1..0..1....1..0..1....1..0..0
..1..0..1....1..1..0....1..0..1....1..0..1....0..1..1....0..1..1....0..0..0
..0..1..0....1..0..1....0..1..0....0..1..0....1..0..1....1..0..1....1..0..1
..1..0..0....0..1..0....1..1..1....1..1..1....0..1..0....0..1..0....0..1..0
..0..1..0....1..0..1....0..0..0....0..1..0....1..1..1....1..1..1....1..1..1
..1..0..1....0..0..0....1..0..1....1..0..1....0..0..0....0..1..0....0..0..0
CROSSREFS
Column 1 of A260138.
Sequence in context: A080469 A341283 A260138 * A320632 A368832 A188633
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 17 2015
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 25 11:48 EDT 2024. Contains 373701 sequences. (Running on oeis4.)