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!)
A243722 Number of length n+2 0..3 arrays with no three unequal elements in a row and no three equal elements in a row and new values 0..3 introduced in 0..3 order. 1

%I #8 Nov 03 2018 08:39:39

%S 3,6,12,25,53,115,253,564,1268,2871,6531,14911,34127,78250,179644,

%T 412797,949145,2183355,5024025,11563144,26617508,61278283,141084439,

%U 324844263,747976187,1722312558,3965923308,9132346753,21029284637,48424978627

%N Number of length n+2 0..3 arrays with no three unequal elements in a row and no three equal elements in a row and new values 0..3 introduced in 0..3 order.

%H R. H. Hardin, <a href="/A243722/b243722.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 3*a(n-2) - 4*a(n-3) - 3*a(n-4).

%F Empirical g.f.: x*(3 - 9*x^2 - 5*x^3) / ((1 - x - x^2)*(1 - x - 3*x^2)). - _Colin Barker_, Nov 03 2018

%e Some solutions for n=6:

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

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

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

%e ..1....0....1....0....0....0....1....0....0....2....1....2....2....1....2....0

%e ..1....1....0....1....1....1....2....0....2....2....1....2....2....1....1....0

%e ..0....0....0....1....1....1....2....2....0....0....0....1....3....2....1....1

%e ..0....0....2....2....0....0....0....0....0....2....0....1....2....1....2....1

%e ..1....2....2....2....0....1....0....2....3....0....2....2....2....2....1....0

%Y Column 3 of A243729.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 09 2014

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 25 17:53 EST 2024. Contains 370332 sequences. (Running on oeis4.)