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A129433 Number of isomorphism classes of 6-regular multigraphs of order n, loops allowed. 8
1, 4, 13, 66, 384, 3369, 40365, 675368, 14843787, 412444439, 14024069358, 570883006810, 27368160642418, 1525274952640101, 97766102550401217, 7141331463919539567 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Computed using software at http://users.cecs.anu.edu.au/~bdm/nauty/

LINKS

Table of n, a(n) for n=1..16.

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_n[S_6] * S_{3n}[S_2]\} [Equation (5.8) of Read 1959]

CROSSREFS

Cf. A129432, A129422, A129427, A129429, A129431, A129435, A129437

Sequence in context: A005035 A222771 A052415 * A157311 A318600 A096805

Adjacent sequences:  A129430 A129431 A129432 * A129434 A129435 A129436

KEYWORD

nonn

AUTHOR

Brendan McKay, Apr 15 2007

EXTENSIONS

Using the formula, new terms a(13), Oct 05 2009, and a(14)..a(16), Nov 09 2009, were computed in MAGMA by Jason Kimberley.

STATUS

approved

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Last modified June 18 18:52 EDT 2019. Contains 324215 sequences. (Running on oeis4.)