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!)
A184096 Half the number of n X n toroidal binary arrays with each element having the sum of its vertical neighbors equal to the sum of its horizontal neighbors 0
1, 2, 7, 18, 31, 98, 127, 450, 511, 1922, 2047, 7938, 8191, 32258, 32767, 130050, 131071, 522242, 524287, 2093058 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Half the number of solutions in 0..1 of a 1-d velocity-one wave equation utt=uxx on a periodic grid

Diagonal of A184097

LINKS

Table of n, a(n) for n=1..20.

FORMULA

Empirical G.f.: x*(1+2*x-2*x^2)*(1+2*x^2)/(1-x)/(1+x)/(1-2*x)/(1+2*x)/(1-2*x^2). [Colin Barker, Feb 17 2012]

EXAMPLE

Some solutions for 5X5

..1..0..0..1..1....1..0..0..0..1....1..0..0..0..0....1..1..1..0..0

..0..0..1..1..1....1..1..0..0..0....0..1..0..0..0....0..1..1..1..0

..0..1..1..1..0....0..1..1..0..0....0..0..1..0..0....0..0..1..1..1

..1..1..1..0..0....0..0..1..1..0....0..0..0..1..0....1..0..0..1..1

..1..1..0..0..1....0..0..0..1..1....0..0..0..0..1....1..1..0..0..1

CROSSREFS

Sequence in context: A001114 A107615 A195605 * A136583 A307684 A141631

Adjacent sequences:  A184093 A184094 A184095 * A184097 A184098 A184099

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 09 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 4 19:17 EDT 2020. Contains 336202 sequences. (Running on oeis4.)