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!)
A317818 Number of nX3 0..1 arrays with every element unequal to 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1
1, 16, 35, 135, 356, 1113, 3150, 9484, 27522, 81798, 239572, 707803, 2080838, 6134691, 18056895, 53200116, 156648460, 461423021, 1358857346, 4002288009, 11787108436, 34715792064, 102243257032, 301126862896, 886870040361 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 3 of A317823.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +7*a(n-2) +2*a(n-3) -10*a(n-4) -14*a(n-5) -16*a(n-6) -25*a(n-7) +36*a(n-8) +42*a(n-9) -26*a(n-10) +62*a(n-11) +10*a(n-12) -28*a(n-13) +20*a(n-14) -16*a(n-15) +4*a(n-16) for n>18
EXAMPLE
Some solutions for n=5
..0..1..1. .0..1..1. .0..1..0. .0..0..1. .0..0..1. .0..1..0. .0..0..0
..1..0..0. .1..0..0. .1..0..0. .1..0..0. .1..0..0. .1..0..1. .1..1..1
..0..0..1. .0..0..1. .0..1..1. .1..0..0. .1..0..1. .0..0..1. .0..1..1
..1..1..1. .0..1..0. .1..1..0. .0..0..1. .0..1..1. .0..0..1. .0..1..0
..0..0..0. .1..1..0. .0..0..1. .0..1..0. .1..0..0. .1..0..0. .0..1..0
CROSSREFS
Cf. A317823.
Sequence in context: A105509 A337024 A219316 * A236463 A070588 A250432
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 07 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 February 25 06:40 EST 2024. Contains 370310 sequences. (Running on oeis4.)