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A005975 Number of interval graphs on n unlabeled nodes.
(Formerly M1224)
2
1, 2, 4, 10, 27, 92, 369, 1807, 10344, 67659, 491347, 3894446, 33278992, 304256984, 2960093835, 30523315419, 332524557107, 3816805831381, 46048851321131, 582691924941142, 7717878059859874, 106806430860694984, 1541683193805924288, 23173865491070682522 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

REFERENCES

Hanlon, Phil; Counting interval graphs. Trans. Amer. Math. Soc. 272 (1982), no. 2, 383-426.

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

R. W. Robinson, Table of n, a(n) for n = 1..30

CROSSREFS

Sequence in context: A057786 A007776 A123428 * A048193 A123411 A128933

Adjacent sequences:  A005972 A005973 A005974 * A005976 A005977 A005978

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

a(21) onwards added by N. J. A. Sloane (njas(AT)research.att.com), Oct 19 2006 from the Robinson reference

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Last modified February 17 07:30 EST 2012. Contains 205998 sequences.