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!)
A204749 Number of (n+2) X 5 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
102, 31, 22, 27, 35, 48, 69, 103, 158, 247, 391, 624, 1001, 1611, 2598, 4195, 6779, 10960, 17725, 28671, 46382, 75039, 121407, 196432, 317825, 514243, 832054, 1346283, 2178323, 3524592, 5702901, 9227479, 14930366, 24157831, 39088183 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 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*(102 - 173*x - 40*x^2 + 85*x^3 + 12*x^4) / ((1 - x)*(1 - x - x^2)). - Colin Barker, Jun 09 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

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

CROSSREFS

Cf. A204754.

Sequence in context: A015164 A325776 A325775 * A244949 A266017 A144469

Adjacent sequences:  A204746 A204747 A204748 * A204750 A204751 A204752

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 January 23 21:06 EST 2022. Contains 350515 sequences. (Running on oeis4.)