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A003317 Number of unlabeled minimally 2-connected graphs with n nodes (also called "blocks").
(Formerly M0799)
4
1, 1, 2, 3, 6, 12, 28, 68, 184, 526, 1602, 5075, 16711, 56428, 195003, 685649, 2447882, 8850157, 32359428, 119492766, 445236635, 1672636369, 6331624545, 24138404479, 92640942148, 357805122286, 1390318899884, 5433781135206 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,3

COMMENTS

Pootheri reference also contains the edge breakups for each term.

REFERENCES

A. M. Hobbs, A catalog of minimal blocks, J. Res. National Bureau Standards, B 77 (1973), 53-60.

S. K. Pootheri, Characterizing and counting classes of unlabeled 2-connected graphs, Ph. D. Dissertation, University of Georgia. (Under the direction of Robert W. Robinson, rwr(AT)cs.uga.edu)

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=3..30.

A. M. Hobbs, A catalog of minimal blocks, J. Res. National Bureau Standards, B 77 (1973), 53-60. (Annotated scanned copy)

Hu, Guan Zhang; Liu, Guo Qing; Liu, Shi; He, Jian Ping; Enumeration of minimally 2-connected graphs by means of group theory, (Chinese) Acta Math. Appl. Sinica 12 (1989), no. 2, 164-173.

CROSSREFS

Cf. A054316, A054317, A002218.

Sequence in context: A014280 A073431 A273873 * A145062 A300323 A261230

Adjacent sequences:  A003314 A003315 A003316 * A003318 A003319 A003320

KEYWORD

nonn,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Sridar K. Pootheri (sridar(AT)math.uga.edu), Feb 25 2000

STATUS

approved

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Last modified November 17 04:01 EST 2018. Contains 317275 sequences. (Running on oeis4.)