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A004115 Number of unlabeled rooted nonseparable graphs with n nodes.
(Formerly M3592)
3
0, 1, 1, 4, 22, 178, 2278, 46380, 1578060, 92765486, 9676866173, 1821391854302, 625710416245358, 395761853562201960, 464128290507379386872, 1015085639712281997464676, 4160440039279630394986003604 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

REFERENCES

R. W. Robinson, personal communication.

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1976.

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..26

R. W. Robinson, Rooted non-separable graphs - computer printout

CROSSREFS

Cf. A002218, A013922.

Sequence in context: A294343 A259842 A125863 * A222885 A235329 A220231

Adjacent sequences:  A004112 A004113 A004114 * A004116 A004117 A004118

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified October 15 11:03 EDT 2018. Contains 316224 sequences. (Running on oeis4.)