  When my brilliant student Thotsaporn "Aek" Thanatipanonda asked me about how
many ways can one cover n identical twins, it rang a Bell back to 1981 (see the
article). As usual, the method of teaching the computer how to do its own
combinatorics, and to use "analysis" (that is really part of discrete math) to
enumerate challenging combinatorial objects is even more interesting than the
theorems and even the algorithm. Of course, formulas are dead, long live
algorithms! But even algorithms are dead, long live meta-algorithms!!
