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A006610
Number of n-node trees not determined by their spectra.
(Formerly M1959)
0
0, 0, 0, 0, 0, 0, 0, 2, 10, 8, 60, 119, 415, 826, 2470, 5246, 14944, 32347, 84118
OFFSET
1,8
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
C. Godsil and B. D. McKay, Some computational results on the spectra of graphs, pp. 73-92 of Combinatorial Mathematics IV (Adelaide 1975), Lect. Notes Math., 560 (1976).
Jürgen Jost, Raffaella Mulas, and Leo Torres, Spectral theory of the non-backtracking Laplacian for graphs, arXiv:2203.10824 [math.SP], 2022.
CROSSREFS
Sequence in context: A316967 A189711 A092939 * A227716 A033839 A196367
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
Existing terms verified and a(19) from Sean A. Irvine, May 14 2017
STATUS
approved