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!)
A333738 Number of non-isomorphic n X n nonnegative integer symmetric matrices with all row and column sums equal to n up to permutations of rows and columns. 1
1, 1, 2, 5, 33, 556, 31781, 5882230, 3589936407, 7347418294141, 51304793433150418, 1240428029662246026001, 105148289475978338858008298, 31582581551955332317665959184087 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..13.

EXAMPLE

The a(3) = 5 matrices are:

  [0, 0, 3]  [0, 1, 2]  [0, 1, 2]  [1, 0, 2]  [1, 1, 1]

  [0, 3, 0]  [1, 1, 1]  [1, 2, 0]  [0, 3, 0]  [1, 1, 1]

  [3, 0, 0]  [2, 1, 0]  [2, 0, 1]  [2, 0, 1]  [1, 1, 1]

CROSSREFS

Main diagonal of A333737.

Sequence in context: A198089 A197974 A208985 * A114793 A254429 A298945

Adjacent sequences:  A333735 A333736 A333737 * A333739 A333740 A333741

KEYWORD

nonn,more

AUTHOR

Andrew Howroyd, Apr 08 2020

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 October 4 04:26 EDT 2022. Contains 357237 sequences. (Running on oeis4.)