new feature

[N. J. A. Sloane]

In an attempt to organize the sequences better, I've started adding
links from the database to the index file (Sindx.html).
For example, if you look up A000055 (trees on n nodes,
the new sample sequence on the home page), you will see a link
that points you to the place in the index file where all the
"tree" sequences are listed.  Many more such links (thousands,
in fact) need to be added.

So far I did sequences related to "trees", "core" sequences,
the hexagonal lattice, the 3x+1 problem, and the
Barnes-Wall lattices.

If anyone feels like choosing a category, and sending me a list
of all the sequences in the category, that would be helpful.
If there are more than about 50 sequences then the category
is probably too big.

Neil Sloane

PS I didn't actually do all the "tree" sequences, just
those that were listed in the index to the 1995 book.