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!)
A251203 Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock summing to a nonzero multiple of 2. 1
40, 180, 816, 3728, 17152, 79424, 369920, 1731840, 8144896, 38458368, 182218752, 865931264, 4125491200, 19697254400, 94217240576, 451363012608, 2165141143552, 10397297147904, 49974875258880, 240389177999360, 1157058166521856 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 8*a(n-1) - 12*a(n-2) - 16*a(n-3).
Empirical g.f.: 4*x*(10 - 35*x - 36*x^2) / ((1 - 4*x)*(1 - 4*x - 4*x^2)). - Colin Barker, Nov 26 2018
EXAMPLE
Some solutions for n=4:
..2..1....1..1....2..0....0..1....0..1....2..2....2..0....0..0....2..2....2..1
..1..0....1..1....0..2....1..0....0..1....1..1....0..0....2..2....2..2....1..0
..1..2....0..2....2..2....1..0....2..1....1..1....2..2....2..0....2..2....1..0
..1..0....1..1....2..2....1..0....2..1....1..1....0..2....2..0....2..2....2..1
..2..1....0..2....2..2....0..1....1..0....2..0....2..2....2..2....1..1....1..2
CROSSREFS
Column 1 of A251210.
Sequence in context: A327430 A251210 A211497 * A187510 A187379 A077818
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 30 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 March 29 04:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)