The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A281394 Number of n X 2 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1

%I #8 Feb 18 2019 20:04:22

%S 0,0,6,36,160,676,2692,10352,38868,143276,520736,1871380,6663484,

%T 23545568,82661076,288590204,1002706896,3469289876,11959062188,

%U 41088781264,140757051348,480912678028,1639160372000,5574818816340

%N Number of n X 2 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

%H R. H. Hardin, <a href="/A281394/b281394.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 7*a(n-2) - 6*a(n-3) - 5*a(n-4) + 12*a(n-5) + 4*a(n-6) - 4*a(n-8).

%F Empirical g.f.: 2*x^3*(1 + x - x^2)*(3 - 3*x - x^2) / (1 - 3*x - x^2 + 2*x^4)^2. - _Colin Barker_, Feb 18 2019

%e Some solutions for n=4:

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

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

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

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

%Y Column 2 of A281400.

%K nonn

%O 1,3

%A _R. H. Hardin_, Jan 21 2017

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.

Last modified September 23 21:37 EDT 2023. Contains 365554 sequences. (Running on oeis4.)