The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A236323 Number of (n+1) X (1+1) 0..1 arrays colored with the sum of the upper and lower median values of each 2 X 2 subblock. 1
16, 32, 60, 120, 252, 496, 972, 1960, 3980, 7872, 15676, 31512, 63260, 125840, 251692, 504456, 1009452, 2014560, 4031900, 8069112, 16136636, 32249392, 64530060, 129075560, 258121932, 516130816, 1032513532, 2064979160, 4129750620 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-2) + 2*a(n-3) + 8*a(n-4).
Empirical g.f.: 4*x*(4 + 8*x + 11*x^2 + 14*x^3) / ((1 - 2*x)*(1 + 2*x + 3*x^2 + 4*x^3)). - Colin Barker, Oct 21 2018
EXAMPLE
Some solutions for n=5:
..1..1....1..1....1..0....1..1....1..1....0..0....1..1....0..0....0..0....1..1
..0..1....0..1....0..1....0..1....0..1....0..0....0..1....0..1....0..1....1..1
..0..1....0..0....0..0....1..0....1..0....1..1....0..1....0..1....0..1....0..0
..0..0....1..1....1..1....1..1....0..0....1..0....1..1....1..1....1..1....1..0
..1..1....1..0....0..1....0..0....1..1....1..0....0..0....0..0....0..0....1..0
..1..0....0..1....0..1....1..0....1..1....0..0....1..0....0..0....1..0....1..1
CROSSREFS
Sequence in context: A224544 A255994 A204645 * A018923 A264901 A339840
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 22 2014
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 May 28 12:20 EDT 2024. Contains 372913 sequences. (Running on oeis4.)