A129435 Number of isomorphism classes of 7-regular multigraphs of order 2n, loops allowed.

4, 101, 12782, 8584767, 20104116089, 122644465172798, 1658339657066189475, 44564623565972592394826, 2193250056291167380214634054, 185389574171283940222059091478222

Offset

1,1

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.

R. C. Read, The enumeration of locally restricted graphs (I), J. London Math. Soc. 34 (1959) 417-436.

Formula

a(n) = N\{S_{2n}[S_7] * S_{7n}[S_2]\}.

Euler transform of A129434. - Andrew Howroyd, Mar 15 2020

Crossrefs

Column k=7 of A167625.

Cf. A129434, A129424, A129427, A129429, A129431, A129433, A129437.

Sequence in context: A363815 A218884 A059105 * A129702 A220776 A180818

Adjacent sequences: A129432 A129433 A129434 * A129436 A129437 A129438

Keyword

nonn,more

Author

Brendan McKay, Apr 15 2007

Extensions

Using equation (5.8) of Read 1959, McKay's terms were verified by, and new term a(6) was computed by Jason Kimberley, Nov 09 2009

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

Status

approved