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!)
A183315 Number of n X 3 binary arrays with an element zero only if there are an even number of ones to its left and an even number of ones above it. 1

%I #8 Mar 27 2018 08:49:31

%S 5,13,43,124,377,1109,3305,9767,28959,85677,253693,750777,2222308,

%T 6577131,19466625,57614249,170519517,504678557,1493676557,4420766649,

%U 13083945331,38723960052,114609540289,339204648201,1003928499625

%N Number of n X 3 binary arrays with an element zero only if there are an even number of ones to its left and an even number of ones above it.

%C Column 3 of A183322.

%H R. H. Hardin, <a href="/A183315/b183315.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = a(n-1) + 9*a(n-2) - 3*a(n-3) - 21*a(n-4) + a(n-5) + 13*a(n-6) + a(n-7) - a(n-8).

%F Empirical g.f.: x*(5 + 8*x - 15*x^2 - 21*x^3 + 10*x^4 + 13*x^5 - x^7) / (1 - x - 9*x^2 + 3*x^3 + 21*x^4 - x^5 - 13*x^6 - x^7 + x^8). - _Colin Barker_, Mar 27 2018

%e Some solutions for 5 X 3:

%e ..1..1..1....0..1..1....1..1..0....1..1..0....1..1..0....1..1..1....1..1..0

%e ..1..1..1....1..1..1....1..1..0....1..1..0....1..1..1....1..1..1....1..1..1

%e ..0..0..0....1..1..1....0..0..0....0..1..1....1..1..1....0..0..0....0..0..1

%e ..0..1..1....0..1..1....0..0..0....0..1..1....1..1..0....1..1..0....0..0..1

%e ..0..1..1....0..0..1....0..1..1....0..0..1....1..1..0....1..1..1....0..1..1

%Y Cf. A183322.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 03 2011

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 April 24 13:41 EDT 2024. Contains 371957 sequences. (Running on oeis4.)