%I A004936
%S A004936 1,1,1,25,49,49,121,20449,20449,5909761,17631601,17631601,
%T A004936 55190041,55190041,55190041,46414824481,154341336769,154341336769,
%U A004936 427538329,585299972401,585299972401,983889253606081,3438962627443561
%N A004936 Numerator of (binomial(2*n-2,n-1)/n!)^2.
%D A004936 Valtr, Pavel; The probability that n random points in a triangle are 
               in convex position. Combinatorica 16 (1996), no. 4, 567-573.
%H A004936 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               SylvestersFour-PointProblem.html">Link to a section of The World 
               of Mathematics.</a>
%Y A004936 Sequence in context: A143278 A106632 A090093 this_sequence A062058 A069063 
               A064937
%Y A004936 Adjacent sequences: A004933 A004934 A004935 this_sequence A004937 A004938 
               A004939
%K A004936 nonn
%O A004936 1,4
%A A004936 N. J. A. Sloane (njas(AT)research.att.com).