David C. Haws 2/2/2012
Program to generate all binary trees with labeled leafs.

Uses simple DFS to insert leafs one by one. 


Test run:
    $ for i in $(seq 3 10);do echo $i;time ./genbintrees $i | wc -l;done

3 1         real	0m0.002s    user	0m0.001s    sys	0m0.003s
4 3         real	0m0.004s    user	0m0.001s    sys	0m0.002s
5 15        real	0m0.004s    user	0m0.001s    sys	0m0.002s
6 105       real	0m0.003s    user	0m0.001s    sys	0m0.003s
7 945       real	0m0.013s    user	0m0.007s    sys	0m0.004s
8 10395     real	0m0.089s    user	0m0.073s    sys	0m0.038s
9 135135    real	0m1.154s    user	0m0.996s    sys	0m0.462s
10 2027025  real	0m18.180s   user	0m15.641s   sys	0m6.940s


To get the raw Pauplin vectors:
    $ ./genbintrees 8 | grep "Pauplin Vector (dec)" | sed 's/Pauplin Vector (dec): //'