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!)
A203820 Number of (n+1)X3 0..3 arrays with no 2X2 subblock having equal diagonal elements or equal antidiagonal elements 1
1296, 27216, 571536, 12002256, 252047376, 5292994896, 111152892816, 2334210749136, 49018425731856, 1029386940368976, 21617125747748496, 453959640702718416, 9533152454757086736, 200196201549898821456 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A203826

LINKS

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

FORMULA

Empirical: a(n) = 1296*21^(n-1)

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A223560 A016912 A330980 * A017056 A223596 A265471

Adjacent sequences:  A203817 A203818 A203819 * A203821 A203822 A203823

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 06 2012

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 May 25 02:01 EDT 2020. Contains 334581 sequences. (Running on oeis4.)