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!)
A202797 Number of n X 3 binary arrays with every one adjacent to another one horizontally or vertically. 1
4, 36, 250, 1718, 11988, 83518, 581518, 4049700, 28202318, 196400270, 1367728548, 9524845126, 66330898142, 461927514284, 3216857242006, 22402152254494, 156008298702684, 1086439775514766, 7565952552767646, 52689195775528564 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 3 of A202802.
LINKS
FORMULA
Empirical: a(n) = 7*a(n-1) -3*a(n-2) +19*a(n-3) -3*a(n-4) +25*a(n-5) +24*a(n-6) -22*a(n-7) -16*a(n-8).
Empirical g.f.: 2*x*(2 + 4*x + 5*x^2 + 20*x^4 + 7*x^5 - 16*x^6 - 8*x^7) / (1 - 7*x + 3*x^2 - 19*x^3 + 3*x^4 - 25*x^5 - 24*x^6 + 22*x^7 + 16*x^8). - Colin Barker, Jun 01 2018
EXAMPLE
Some solutions for n=5:
..0..0..0....0..1..0....0..0..1....0..1..1....0..1..1....0..0..1....0..0..0
..1..0..0....1..1..1....0..0..1....0..1..0....0..0..1....0..0..1....1..0..0
..1..0..0....0..0..1....1..0..1....1..0..0....1..1..0....0..1..0....1..1..1
..0..1..1....0..1..0....1..1..1....1..1..1....0..0..0....0..1..1....1..1..1
..0..1..0....0..1..1....0..1..0....0..0..1....0..1..1....0..0..1....0..1..0
CROSSREFS
Cf. A202802.
Sequence in context: A295411 A218516 A119579 * A294832 A075144 A183496
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 24 2011
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 18 00:08 EDT 2024. Contains 374377 sequences. (Running on oeis4.)