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!)
A304671 Number of nX3 0..1 arrays with every element unequal to 0, 2, 3, 5 or 6 king-move adjacent elements, with upper left element zero. 1
1, 7, 13, 23, 45, 131, 337, 883, 2389, 6599, 18393, 51475, 144777, 408787, 1156245, 3275327, 9287881, 26355499, 74822993, 212488499, 603573125, 1714703255, 4871817065, 13842752035, 39334524393, 111773515363, 317623880677 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 3 of A304676.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) -8*a(n-3) -13*a(n-4) +20*a(n-5) +21*a(n-6) +4*a(n-7) -30*a(n-8) -44*a(n-9) -17*a(n-10) +72*a(n-11) +116*a(n-12) -20*a(n-13) -72*a(n-14) -52*a(n-15) -12*a(n-16) +24*a(n-17) +8*a(n-18) for n>19
EXAMPLE
Some solutions for n=5
..0..0..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..0..0
..0..0..0. .1..0..1. .1..1..0. .1..0..1. .0..1..1. .1..0..1. .1..1..1
..0..0..0. .1..1..1. .0..0..0. .1..1..1. .0..0..1. .1..1..1. .1..1..1
..0..0..0. .0..0..1. .0..1..0. .1..0..0. .1..1..0. .1..0..1. .0..0..0
..1..1..1. .0..0..1. .1..0..1. .1..0..1. .0..1..0. .0..1..0. .0..0..0
CROSSREFS
Cf. A304676.
Sequence in context: A227786 A339148 A270792 * A075642 A316118 A265766
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 16 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 June 20 13:44 EDT 2024. Contains 373527 sequences. (Running on oeis4.)