A129423 Number of isomorphism classes of connected 7-regular loopless multigraphs of order 2n.

1, 7, 263, 90614, 165041329, 861723619902, 10351918806321621, 253216618556625008961, 11542463442106815907796586, 915449471830886733265105097578

Offset

1,2

Comments

Initial terms computed using software at http://users.cecs.anu.edu.au/~bdm/nauty/

Links

Table of n, a(n) for n=1..10.

Brendan McKay and Adolfo Piperno, Nauty and Traces

Formula

Inverse Euler transform of A129424. - Andrew Howroyd, Mar 21 2020

Prog

(nauty/bash) geng -c -d1 $[2*$n] -q | multig -r7 -u # Natan Arie Consigli, Dec 20 2019

Crossrefs

Column k=7 of A328682.

Cf. A129424, A129434, A000421, A129417, A129419, A129421, A129425, A328682.

Sequence in context: A269576 A130741 A003385 * A324095 A290880 A231486

Adjacent sequences: A129420 A129421 A129422 * A129424 A129425 A129426

Keyword

nonn

Author

Brendan McKay, Apr 15 2007

Extensions

a(7)-a(10) from Andrew Howroyd, Mar 21 2020

Status

approved