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!)
A184043 1/9 the number of (n+1) X 5 0..2 arrays with all 2 X 2 subblocks having the same four values. 1
45, 51, 61, 81, 117, 189, 325, 597, 1125, 2181, 4261, 8421, 16677, 33189, 66085, 131877, 263205, 525861, 1050661, 2100261, 4198437, 8394789, 16785445, 33566757, 67125285, 134242341, 268468261, 536920101, 1073807397, 2147581989, 4295098405 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A184048.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).

Conjectures from Colin Barker, Apr 10 2018: (Start)

G.f.: x*(45 - 84*x - 92*x^2 + 168*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).

a(n) = 3*2^(n/2) + 2^(n+1) + 37 for n even.

a(n) = 2^(n+1) + 2^((n+3)/2) + 37 for n odd.

(End)

EXAMPLE

Some solutions for 7 X 5:

..0..1..0..1..0....2..0..2..0..2....1..2..1..2..1....0..0..0..1..0

..0..1..0..1..0....2..2..2..2..2....0..0..0..0..0....1..1..1..0..1

..1..0..1..0..1....0..2..0..2..0....1..2..1..2..1....0..0..0..1..0

..0..1..0..1..0....2..2..2..2..2....0..0..0..0..0....1..1..1..0..1

..0..1..0..1..0....0..2..0..2..0....2..1..2..1..2....0..0..0..1..0

..0..1..0..1..0....2..2..2..2..2....0..0..0..0..0....1..1..1..0..1

..1..0..1..0..1....2..0..2..0..2....2..1..2..1..2....0..0..0..1..0

CROSSREFS

Cf. A184048.

Sequence in context: A274368 A214572 A295493 * A345482 A295802 A242267

Adjacent sequences: A184040 A184041 A184042 * A184044 A184045 A184046

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 08 2011

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 February 2 03:35 EST 2023. Contains 359997 sequences. (Running on oeis4.)