A221961 - OEIS

%I #11 Feb 24 2018 10:12:16

%S 1,3,18,149,1390,13377

%N Number of n X n symmetric lonesum ternary matrices.

%H H. K. Kim, D. S. Krotov and J. Y. Lee, <a href="http://dx.doi.org/10.1016/j.laa.2012.11.027">Matrices uniquely determined by their lonesums</a>, Linear Algebra and its Applications, 438 (2013) no 7, 3107-3123

%F Kim et al. (2013) give a formula.

%Y Cf. A000629 (the binary case).

%Y See also A299906, A299907 for the general binary case.

%K nonn,more

%O 0,2

%A _N. J. A. Sloane_, Feb 05 2013