A129431 Number of isomorphism classes of 5-regular multigraphs of order 2n, loops allowed.

3, 32, 727, 42703, 5988679, 1639714425, 757559332934, 541249158493444, 564262722366313620, 822164422526588575949, 1618567795242262158194706, 4188563149202582371775198174, 13926836449718334345103644635724, 58360974360850795591633858610837541

Offset

1,1

Comments

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

Links

Table of n, a(n) for n=1..14.

R. C. Read, The enumeration of locally restricted graphs (I), J. London Math. Soc. 34 (1959) 417-436. [From Jason Kimberley, Oct 05 2009]

Formula

a(n) = N\{S_{2n}[S_5] * S_{5n}[S_2]\}. - Jason Kimberley, Oct 05 2009

Euler transform of A129430. - Andrew Howroyd, Mar 15 2020

Crossrefs

Column k=5 of A167625.

Cf. A129430, A129420, A129427, A129429, A129433, A129435, A129437.

Sequence in context: A370462 A295385 A331799 * A297558 A283716 A352019

Adjacent sequences: A129428 A129429 A129430 * A129432 A129433 A129434

Keyword

nonn

Author

Brendan McKay, Apr 15 2007

Extensions

Using equation (5.8) of Read 1959, new terms a(8)-a(10) were computed in MAGMA during 2009 by Jason Kimberley, Dec 22 2010

a(11)-a(14) from Andrew Howroyd, Mar 21 2020

Status

approved