%N Triangle read by columns: Distinct classifications of N elements containing exactly R binary partitions.
%C The bottom of each column is marked by a single 0 in this sequence. Value is 0 for all (N,R) for which N is greater than 2^R.
%C See note on efficient computation in A171871.
%H R. Munafo, <a href="http://mrob.com/pub/math/seq-a005646.html">Classifications of N Elements</a>
%Y First term in each column is A000055(R+1).
%Y Column 4 shares terms with A034189, column 5 with A034190.
%A _Robert Munafo_, Jan 21 2010