login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A231950 Number of (n+1)X(1+1) 0..1 arrays with every element equal to some horizontal, vertical, diagonal or antidiagonal neighbor, with top left element zero 8

%I

%S 4,18,64,236,888,3336,12512,46928,176032,660320,2476928,9291200,

%T 34852224,130734208,490397184,1839529216,6900259328,25883567616,

%U 97091868672,364201376768,1366156040192,5124588881920,19222848954368,72106842214400

%N Number of (n+1)X(1+1) 0..1 arrays with every element equal to some horizontal, vertical, diagonal or antidiagonal neighbor, with top left element zero

%C Column 1 of A231957

%H R. H. Hardin, <a href="/A231950/b231950.txt">Table of n, a(n) for n = 1..210</a>

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

%e Some solutions for n=7

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

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

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 15 2013

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 November 13 17:34 EST 2019. Contains 329106 sequences. (Running on oeis4.)