%I #9 Aug 30 2018 15:02:58
%S 1,1,1,1,2,3,8,16,40,89,214,498,1194,2849,6890,16706,40820,100134,
%T 246930,611215,1518972,3787278,9473250,23762348,59763611,150670704,
%U 380716008,963993526,2445626469,6215681848,15824165262
%N Shifts left 2 places under "BHK" (reversible, identity, unlabeled) transform.
%H Andrew Howroyd, <a href="/A032104/b032104.txt">Table of n, a(n) for n = 1..200</a>
%H C. G. Bower, <a href="/transforms2.html">Transforms (2)</a>
%H <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>
%o (PARI)
%o BHK(p)={p + (1/(1-p) - (1+p)/subst(1-p, x, x^2))/2}
%o seq(n)={my(p=1+O(x^(n%2)));for(i=1, n\2, p=1+x+x*BHK(x*p)); Vec(p)} \\ _Andrew Howroyd_, Aug 30 2018
%K nonn,eigen
%O 1,5
%A _Christian G. Bower_