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A004300 Number of symmetric irreducible diagrams with 2n nodes.
(Formerly M1758)
3
1, 1, 2, 7, 22, 96, 380, 1853, 8510, 44940, 229836, 1296410, 7211116, 43096912, 256874200, 1617413773, 10226972110, 67542201972, 449809389740, 3104409032126 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
REFERENCES
M. Klazar, Non-P-recursiveness of numbers of matchings or linear chord diagrams with many crossings, Advances in Appl. Math., Vol. 30 (2003), pp. 126-136.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
R. R. Stein, On a class of linked diagrams, I. Enumeration, J. Combin. Theory, A 24 (1978), 357-366.
R. R. Stein and C. J. Everett, On a class of linked diagrams, II. Asymptotics, Discrete Math., 21 (1978), 309-318.
LINKS
Jonathan Burns, Egor Dolzhenko, Natasa Jonoska, Tilahun Muche, and Masahico Saito, Four-Regular Graphs with Rigid Vertices Associated to DNA Recombination, Discrete Applied Mathematics, Volume 161, Issues 10-11, July 2013, Pages 1378-1394; and preprint, 2011.
Jonathan Burns and Tilahun Muche, Counting Irreducible Double Occurrence Words, arXiv preprint arXiv:1105.2926 [math.CO], 2011.
CROSSREFS
Cf. A000699.
Sequence in context: A150333 A057787 A217138 * A049369 A327697 A308548
KEYWORD
nonn,nice,easy
AUTHOR
STATUS
approved

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Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)