login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A204751 Number of (n+2) X 7 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
342, 38, 35, 40, 48, 61, 82, 116, 171, 260, 404, 637, 1014, 1624, 2611, 4208, 6792, 10973, 17738, 28684, 46395, 75052, 121420, 196445, 317838, 514256, 832067, 1346296, 2178336, 3524605, 5702914, 9227492, 14930379, 24157844, 39088196 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A204754.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) - a(n-3) for n > 5.

Empirical g.f.: x*(342 - 646*x - 41*x^2 + 312*x^3 + 6*x^4) / ((1 - x)*(1 - x - x^2)). - Colin Barker, Jun 10 2018

EXAMPLE

Some solutions for n=3:

  0 1 0 1 0 0 1     0 0 1 1 1 0 0     0 0 1 0 1 0 1

  0 1 0 1 0 0 1     0 0 0 1 1 1 0     0 0 1 0 1 0 1

  0 1 0 1 0 0 1     1 0 0 0 1 1 1     0 0 1 0 1 0 1

  0 1 0 1 0 0 1     1 1 0 0 0 1 1     0 0 1 0 1 0 1

  0 1 0 1 0 0 1     1 1 1 0 0 0 1     0 0 1 0 1 0 1

CROSSREFS

Cf. A204754.

Sequence in context: A015371 A163582 A239271 * A247441 A045106 A137201

Adjacent sequences:  A204748 A204749 A204750 * A204752 A204753 A204754

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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 19 12:57 EDT 2019. Contains 327198 sequences. (Running on oeis4.)