%I #6 Jan 21 2014 13:07:08

%S 1,10,161,3196

%N Number of 321-avoiding extensions of comb K_{s,3}^{alpha}.

%C No formula is presently known.

%H S. Yakoubov, <a href="http://arxiv.org/abs/1310.2979">Pattern Avoidance in Extensions of Comb-Like Posets</a>, arXiv preprint arXiv:1310.2979, 2013

%K nonn,more

%O 1,2

%A _N. J. A. Sloane_, Dec 28 2013