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Search: id:A004110
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| A004110 |
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Number of n-node graphs without endpoints.
(Formerly M1504)
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+0
13
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| 1, 1, 1, 2, 5, 16, 78, 588, 8047, 205914, 10014882, 912908876, 154636289460, 48597794716736, 28412296651708628, 31024938435794151088, 63533059372622888758054, 244916078509480823407040988, 1783406527599529094009748567708
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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a(n) is the number of unlabeled mating graphs with n nodes. A mating graph has no two vertices with identical sets of neighbors. [From Tanya Khovanova (tanyakh(AT)yahoo.com), Oct 23 2008]
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REFERENCES
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F. Harary and E. Palmer, Graphical Enumeration, (1973), compare formula (8.7.11).
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).
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LINKS
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R. W. Robinson, Table of n, a(n) for n = 0..26
Ji Li's Research page [From Tanya Khovanova (tanyakh(AT)yahoo.com), Oct 23 2008]
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CROSSREFS
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Cf. A059166 (n-node connected labeled graphs without endpoints), A059167 (n-node labeled graphs without endpoints), A004108 (n-node connected unlabeled graphs without endpoints).
Cf. A006024 = Number of labeled mating graphs with n nodes. [From Tanya Khovanova (tanyakh(AT)yahoo.com), Oct 23 2008]
Sequence in context: A020127 A121396 A054960 this_sequence A048754 A037075 A115894
Adjacent sequences: A004107 A004108 A004109 this_sequence A004111 A004112 A004113
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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