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!)
A204748 Number of (n+2) X 4 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..1 introduced in row major order. 1
61, 46, 31, 28, 38, 49, 70, 106, 159, 248, 394, 625, 1002, 1614, 2599, 4196, 6782, 10961, 17726, 28674, 46383, 75040, 121410, 196433, 317826, 514246, 832055, 1346284, 2178326, 3524593, 5702902, 9227482, 14930367, 24157832, 39088186, 63246001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A204754.

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) +a(n-3) -a(n-4) -a(n-5) for n>8.

Empirical g.f.: x*(61 - 15*x - 76*x^2 - 110*x^3 - 6*x^4 + 59*x^5 + 32*x^6 + 8*x^7) / ((1 - x)*(1 - x - x^2)*(1 + x + x^2)). - Colin Barker, Jun 09 2018

EXAMPLE

Some solutions for n=3:

..0..0..0..0....0..1..1..1....0..0..1..1....0..0..0..0....0..0..0..0

..0..0..0..0....0..0..1..1....0..0..1..1....1..1..1..1....1..1..1..1

..1..1..1..1....0..0..0..1....0..0..1..1....1..1..1..1....0..0..0..0

..0..0..0..0....1..0..0..0....0..0..1..1....0..0..0..0....1..1..1..1

..1..1..1..1....1..1..0..0....0..0..1..1....1..1..1..1....0..0..0..0

CROSSREFS

Cf. A204754.

Sequence in context: A199749 A303687 A033381 * A276471 A122568 A075028

Adjacent sequences: A204745 A204746 A204747 * A204749 A204750 A204751

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 18 2012

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 1 18:04 EST 2023. Contains 359995 sequences. (Running on oeis4.)