# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a111554 Showing 1-1 of 1 %I A111554 #10 Aug 26 2014 10:16:36 %S A111554 1,2,10,72,632,6352,70912,864192,11371072,160333952,2409420032, %T A111554 38428442112,648333665792,11538313372672,216092576714752, %U A111554 4249731095212032,87591291183296512,1888669450881032192 %N A111554 Column 1 of triangle A111553. %C A111554 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 A111554 (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 A111554 Cf. A111553. %K A111554 nonn %O A111554 0,2 %A A111554 _Paul D. Hanna_, Aug 07 2005 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE