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!)
A318540 Number of nX3 0..1 arrays with every element unequal to 0, 1, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1

%I

%S 3,3,6,13,26,52,107,218,442,899,1829,3720,7565,15384,31288,63632,

%T 129408,263180,535236,1088521,2213749,4502149,9156120,18621004,

%U 37869943,77016935,156631035,318543977,647829886,1317505875,2679440650,5449237333

%N Number of nX3 0..1 arrays with every element unequal to 0, 1, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 3 of A318545.

%H R. H. Hardin, <a href="/A318540/b318540.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +3*a(n-3) +a(n-4) +3*a(n-5) +a(n-7) for n>8

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A318545.

%K nonn

%O 1,1

%A _R. H. Hardin_, Aug 28 2018

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 August 18 16:18 EDT 2022. Contains 356215 sequences. (Running on oeis4.)