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 A217246 Number of highly irregular connected graphs with n nodes. 0
 1, 1, 0, 1, 0, 1, 0, 3, 3, 13, 21, 110, 474, 2545, 18696, 136749, 1447003, 18772435, 303050079, 6239596472 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,8 COMMENTS A connected graph is highly irregular if the neighbors of each vertex have distinct degrees. Such graphs exist on all orders except 3, 5 and 7. [from the McKay link] LINKS Avraham Itzhakov and Michael Codish, Breaking Symmetries in Graph Search with Canonizing Sets, arXiv:1511.08205 [cs.AI], 2015-2016. Brendan McKay, Combinatorial Data (on graphs); see bottom of page. Eric Weisstein's World of Mathematics, Highly Irregular Graph EXAMPLE a(4) = 1, the only such graph is the linear graph: o--o--o--o CROSSREFS Sequence in context: A209390 A095336 A072552 * A186743 A219314 A288146 Adjacent sequences: A217243 A217244 A217245 * A217247 A217248 A217249 KEYWORD more,nonn AUTHOR Joerg Arndt, Mar 16 2013 EXTENSIONS a(16)-a(19) from Michael Codish, Dec 01 2015 a(20) from Michael Codish, Jan 17 2016 STATUS approved

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Last modified March 29 15:18 EDT 2023. Contains 361599 sequences. (Running on oeis4.)