%I #10 Aug 26 2014 10:16:36
%S 1,2,10,72,632,6352,70912,864192,11371072,160333952,2409420032,
%T 38428442112,648333665792,11538313372672,216092576714752,
%U 4249731095212032,87591291183296512,1888669450881032192
%N Column 1 of triangle A111553.
%C a(n) is the number of increasing strict binary trees with 2n-1 nodes that avoid 132. For more information about increasing strict binary trees with an associated permutation, see A245894. - _Manda Riehl_, Aug 07 2014
%o (PARI) {a(n)=if(n<0,0,(matrix(n+2,n+2,m,j,if(m==j,1,if(m==j+1,-m+1, -(m-j-1)*polcoeff(log(sum(i=0,m,(i+3)!/3!*x^i)),m-j-1))))^-1)[n+2,2])}
%Y Cf. A111553.
%K nonn
%O 0,2
%A _Paul D. Hanna_, Aug 07 2005
|