%I A054761
%S A054761 1,4,13,37,99,254,636,1567,3822,9261,22346
%N A054761 Number of positive braids with n crossings of 5 strands.
%C A054761 The (n+1)-strand braid group B_{n+1} has n generators s_1,...,s_n with 
               relations s_i s_k s_i = s_k s_i s_k for k=i+1, s_i s_k = s_k s_i 
               for k>i+1. The elements are the isotopy classes of (n+1) free strands 
               that are planarily "mixed" (s_i corresponds to the operation of crossing 
               the i-th strand under the (i+1)-th strand)..
%D A054761 F. A. Garside, The braid group and other groups, Quart. Journal Math. 
               Oxford, 1969
%Y A054761 Cf. A000071, A054480.
%Y A054761 Sequence in context: A003727 A103082 A048474 this_sequence A080145 A097551 
               A095126
%Y A054761 Adjacent sequences: A054758 A054759 A054760 this_sequence A054762 A054763 
               A054764
%K A054761 nonn
%O A054761 0,2
%A A054761 Serge Burckel (burckel(AT)univ-reunion.fr), Apr 27 2000