A006824 Number of connected regular bipartite graphs of degree 4 with 2n nodes. (Formerly M3493)

1, 1, 4, 14, 129, 1980, 62611, 2806490, 158937213, 10773251972, 855658082615, 78558949838723, 8251166737356319, 982806379842257309, 131756174189661102281, 19748565896506014747623, 3289970433888731383271400, 605948436052375098046655323, 122796503871896458570959144266

Offset

4,3

References

CRC Handbook of Combinatorial Designs, 1996, p. 648.

I. A. Faradzev, Constructive enumeration of combinatorial objects, pp. 131-135 of Problèmes combinatoires et théorie des graphes (Orsay, 9-13 Juillet 1976). Colloq. Internat. du C.N.R.S., No. 260, Centre Nat. Recherche Scient., Paris, 1978.

H. Gropp, On tactical configurations, regular bipartite graphs and (v,k,even)-designs, Discr. Math., 155 (1996), 81-98.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=4..22.

B. D. McKay and E. Rogoyski, Latin squares of order ten, Electron. J. Combinatorics, 2 (1995) #N3.

M. Meringer, Tables of Regular Graphs

Formula

Inverse Euler transform of A333730. - Andrew Howroyd, Apr 03 2020

Crossrefs

Column 4 of A008326.

Cf. A006823, A006825, A333730.

Sequence in context: A137048 A137056 A302021 * A333730 A344201 A254718

Adjacent sequences: A006821 A006822 A006823 * A006825 A006826 A006827

Keyword

nonn,hard,nice

Author

N. J. A. Sloane

Extensions

Terms a(12) and beyond from Andrew Howroyd, Apr 03 2020

Status

approved