|
%I #13 Oct 20 2014 17:15:11
%S 1,1,2,5,15,52,203,877,4140,21147,115975,678570,4213597,27644436,
%T 190899266,1382956734,10480097431,82863928963,682058946982,
%U 5832425824171,51718812364549
%N Number of set partitions of {1, ..., n} that avoid enhanced 7-crossings (or enhanced 7-nestings)
%H M. Bousquet-Mélou and G. Xin, <a href="http://arXiv.org/abs/math.CO/0506551">On partitions avoiding 3-crossings</a>, math.CO/0506551.
%H Sophie Burrill, Sergi Elizalde, Marni Mishna and Lily Yen, <a href="http://arxiv.org/abs/1108.5615">A generating tree approach to k-nonnesting partitions and permutations</a>, arXiv preprint arXiv:1108.5615, 2011
%H W. Chen, E. Deng, R. Du, R. P. Stanley, and C. Yan, <a href="http://arXiv.org/abs/math.CO/0501230">Crossings and nestings of matchings and partitions</a>, math.CO/0501230
%e There are 27644437 partitions of 13 elements, but a(13)=27644436 because the partition {1,13}{2,12}{3,11}{4,10}{5,9}{6,8} {7} has an enhanced 7-nesting.
%Y Cf. A000110, A108307, A192855, A192865, A192866.
%K nonn
%O 0,3
%A _Marni Mishna_, Jul 11 2011
|
