login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A233675 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the sum of the squares of the edge differences equal to 6. 1
48, 184, 648, 2440, 8712, 32456, 116872, 432456, 1565704, 5768392, 20957064, 76995656, 280355592, 1028180936, 3749152392, 13733970760, 50125386248, 183485530824, 670067844488, 2451649137224, 8956514967816, 32760264743368 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 12*a(n-2) - 4*a(n-3) - 16*a(n-4).

Empirical g.f.: 8*x*(6 + 17*x - 14*x^2 - 28*x^3) / (1 - x - 12*x^2 + 4*x^3 + 16*x^4). - Colin Barker, Oct 11 2018

EXAMPLE

Some solutions for n=5:

..3..1....1..2....2..2....0..1....1..1....3..2....2..1....1..2....3..1....1..1

..2..2....1..0....1..3....0..2....2..0....1..2....3..1....1..3....2..1....2..3

..0..1....1..2....1..2....0..1....2..1....1..0....2..2....2..2....3..1....1..1

..2..1....0..0....0..2....0..2....0..1....2..2....3..1....0..1....3..2....2..3

..0..1....1..2....0..1....1..2....2..1....0..1....2..2....2..2....3..1....2..1

..2..2....1..3....2..1....0..0....3..3....2..2....1..0....1..0....2..2....3..1

CROSSREFS

Column 1 of A233682.

Sequence in context: A131683 A066134 A233682 * A005911 A130566 A233792

Adjacent sequences:  A233672 A233673 A233674 * A233676 A233677 A233678

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 14 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 14 01:55 EDT 2020. Contains 336476 sequences. (Running on oeis4.)