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%I #18 Feb 02 2024 09:27:34
%S 1,1,0,1,1,3,1,3,0,14,8,18,33,75
%N Number of simple connected graphs with n nodes that are integral and triangle-free.
%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
%F (Sage) a243332 = lambda n: sum(1 for g in graphs.nauty_geng(f'-c -t {n}') if sum(m for _,m in g.charpoly().roots(ZZ))==n) # _Max Alekseyev_, Jan 31 2024
%Y Cf. A064731 (integral graphs), A024607 (triangle-free graphs).
%K nonn,more
%O 1,6
%A _Travis Hoppe_ and _Anna Petrone_, Jun 03 2014
%E a(11)-a(14) from _Max Alekseyev_, Feb 02 2024