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!)
A298119 Array read by antidiagonals: T(m,n) = number of Eulerian orientations of the torus grid graph C_m X C_n. 5
4, 8, 8, 16, 18, 16, 32, 44, 44, 32, 64, 114, 148, 114, 64, 128, 308, 548, 548, 308, 128, 256, 858, 2116, 2970, 2116, 858, 256, 512, 2444, 8324, 16892, 16892, 8324, 2444, 512, 1024, 7074, 33028, 98466, 143224, 98466, 33028, 7074 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

In other words, the number of orientations of the m X n torus grid graph in which each vertex has equal indegree and outdegree.

Values are always even since reversing the orientation of each edge will always result in another Eulerian orientation.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..91

Eric Weisstein's World of Mathematics, Torus Grid Graph

EXAMPLE

Array begins:

============================================================

m\n|   1    2     3      4        5         6          7

---|--------------------------------------------------------

1  |   4    8    16     32       64       128        256 ...

2  |   8   18    44    114      308       858       2444 ...

3  |  16   44   148    548     2116      8324      33028 ...

4  |  32  114   548   2970    16892     98466     583412 ...

5  |  64  308  2116  16892   143224   1250228   11091536 ...

6  | 128  858  8324  98466  1250228  16448400  220603364 ...

7  | 256 2444 33028 583412 11091536 220603364 4484823396 ...

...

CROSSREFS

Main diagonal is A054759.

Rows 2..4 are 2*A099754, 2*A170938, A298201.

Cf. A212801, A298117.

Sequence in context: A256816 A098354 A209382 * A089474 A141800 A019197

Adjacent sequences:  A298116 A298117 A298118 * A298120 A298121 A298122

KEYWORD

nonn,tabl

AUTHOR

Andrew Howroyd, Jan 12 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 May 17 06:41 EDT 2022. Contains 353730 sequences. (Running on oeis4.)