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A005219
Number of unlabeled identity unit interval graphs.
2
0, 0, 0, 0, 0, 2, 4, 15, 36, 108, 276, 771, 2044, 5622, 15204, 41835, 114708, 317382, 879008, 2447951, 6833084, 19146910, 53786076, 151537847, 427946916, 1211440440, 3436543336, 9768382171, 27817787344, 79356481542
OFFSET
1,6
REFERENCES
R. W. Robinson, personal communication.
R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1980.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Phil Hanlon, Counting interval graphs, Trans. Amer. Math. Soc. 272 (1982), no. 2, 383-426.
CROSSREFS
Cf. A007122.
Sequence in context: A073814 A181442 A007122 * A153945 A153942 A055466
KEYWORD
nonn,nice
STATUS
approved