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!)
A233253 Number of n X 5 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs). 1

%I #7 Oct 11 2018 04:09:52

%S 36,13952,6049792,2647261184,1159192379392,507618560835584,

%T 222290692443996160,97343107609552486400,42627429627049642295296,

%U 18666938062087506825838592,8174421486934238668125110272

%N Number of n X 5 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).

%H R. H. Hardin, <a href="/A233253/b233253.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 512*a(n-1) - 33792*a(n-2) + 589824*a(n-3).

%F Empirical g.f.: 4*x*(9 - 1120*x + 30720*x^2) / ((1 - 32*x)*(1 - 480*x + 18432*x^2)). - _Colin Barker_, Oct 11 2018

%e Some solutions for n=2:

%e ..0..1..2..4..3....0..1..2..5..3....0..1..2..1..0....0..1..2..4..2

%e ..5..4..3..5..2....2..1..2..0..1....2..1..0..3..0....2..4..0..1..5

%Y Column 5 of A233256.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 06 2013

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 July 23 04:43 EDT 2024. Contains 374544 sequences. (Running on oeis4.)