A005976 - OEIS

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A005976

Number of unlabeled connected interval graphs with n nodes.
(Formerly M1487)

1, 1, 2, 5, 15, 56, 250, 1328, 8069, 54962, 410330, 3317302, 28774874, 266242936, 2616100423, 27205605275, 298569256590, 3449309394415, 41854968275924, 532353636671777, 7083840662453415, 98443312509634266, 1426382369328881332

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

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

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

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

CROSSREFS

Sequence in context: A137533 A121392 A216388 * A351158 A187981 A334155