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
3, 3, 6, 13, 26, 52, 107, 218, 442, 899, 1829, 3720, 7565, 15384, 31288, 63632, 129408, 263180, 535236, 1088521, 2213749, 4502149, 9156120, 18621004, 37869943, 77016935, 156631035, 318543977, 647829886, 1317505875, 2679440650, 5449237333 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A318545.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

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

EXAMPLE

Some solutions for n=5

..0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0

..0..0..0. .0..0..0. .0..0..1. .0..0..0. .0..0..0. .1..0..0. .1..0..0

..0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..1. .0..0..1. .0..0..0

..0..0..1. .0..0..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..0..1

..0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0

CROSSREFS

Cf. A318545.

Sequence in context: A123140 A123289 A096572 * A325879 A325865 A110523

Adjacent sequences:  A318537 A318538 A318539 * A318541 A318542 A318543

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 28 2018

STATUS

approved

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 3 11:18 EDT 2022. Contains 355050 sequences. (Running on oeis4.)