A111554 Column 1 of triangle A111553.

1, 2, 10, 72, 632, 6352, 70912, 864192, 11371072, 160333952, 2409420032, 38428442112, 648333665792, 11538313372672, 216092576714752, 4249731095212032, 87591291183296512, 1888669450881032192

Offset: 0

Author

Paul D. Hanna, Aug 07 2005

Keywords

• nonn

Comments

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

Crossrefs

Cf. A111553.

Programs

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])}