%I #20 Mar 25 2015 16:51:27
%S 0,0,1,3,10,58,314,3798,51609,1716267
%N Number of connected graphs on n vertices whose spectrum has fewer than n distinct eigenvalues.
%C The spectrum refers to the eigenvalues of the adjacency matrix.
%H Travis Hoppe and Anna Petrone, <a href="https://github.com/thoppe/Encyclopedia-of-Finite-Graphs">Encyclopedia of Finite Graphs</a>
%H T. Hoppe and A. Petrone, <a href="http://arxiv.org/abs/1408.3644">Integer sequence discovery from small graphs</a>, arXiv preprint arXiv:1408.3644, 2014
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/GraphSpectrum.html">Graph Spectrum</a>
%Y Cf. A064731 (integral graphs), A242952 (distinct spectrum graphs).
%K nonn,more
%O 1,4
%A _Travis Hoppe_ and _Anna Petrone_, May 27 2014
%E Corrected, original description as the "non-real spectrum" was incorrect, by _Travis Hoppe_, Mar 23 2015