A347692 - OEIS

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A347692

Numbers k such that there is regular 2-graph on k points with smallest eigenvalue rho_2 = -5.

%I #3 Oct 03 2021 15:32:15

%S 16,26,36,76,126,176,276

%N Numbers k such that there is regular 2-graph on k points with smallest eigenvalue rho_2 = -5.

%D Taylor, Donald E. "Regular 2-graphs." Proceedings of the London Mathematical Society 3.2 (1977): 257-274. See Theorem 3.8 and Table 2.

%K nonn,fini,full

%O 1,1

%A _N. J. A. Sloane_, Oct 03 2021