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A005216
Number of unlabeled identity interval graphs with n nodes.
(Formerly M3636)
1
1, 0, 0, 0, 0, 4, 31, 199, 1313, 9158, 68336, 546697, 4682870, 42818887, 416581477, 4298371842, 46896673051, 539527125454, 6528590200432, 82900013695783, 1102289694637302, 15317689255215159, 222056321177147564, 3352587738814695770
OFFSET
1,6
REFERENCES
P. J. Hanlon, 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
Sequence in context: A270669 A298996 A299663 * A124033 A014537 A136284
KEYWORD
nonn
EXTENSIONS
a(21) onward added by N. J. A. Sloane, Oct 19 2006 from the Robinson reference
STATUS
approved