A327604 Number of connected 2n-regular loopless multigraphs on nine unlabeled nodes.

0, 1, 832, 252207, 35241608, 2351580473, 89216898630, 2194653376016, 38376657658125, 509484171323720, 5390386822995890, 47150458233195944, 350827631527584993, 2271025998493100911, 13023793690772493636

Offset

0,3

Comments

There are no (2n+1)-regular graphs satisfying the condition above.

Multigraphs are loopless.

Initial terms computed with 'Nauty and Traces' (see the link).

Links

Table of n, a(n) for n=0..14.

Brendan McKay and Adolfo Piperno, Nauty and Traces

Prog

(nauty/shell) for ((n=0; n<12; n=n+2)); do geng -c -d1 9 -q | multig -r${n} -u; done

Crossrefs

Row n=9 of A328682.

Cf. A324217, A324218.

Sequence in context: A252561 A264318 A264141 * A264064 A325064 A214481

Adjacent sequences: A327601 A327602 A327603 * A327605 A327606 A327607

Keyword

nonn,more,hard

Author

Natan Arie Consigli, Sep 18 2019

Extensions

a(6)-a(14) from Andrew Howroyd, Mar 18 2020

Status

approved