Sequences That Need Extending
Extending Sequences
IMPORTANT:
Thousands of people use the sequence database every day.
Please take great care that the terms you send are absolutely correct.
The standards are those of a mathematics reference work.
These sequences (with keyword "more" need extending.
If possible please use the
form
when sending extensions or comments.
For other ways in which you could help, please see the
List of Future Projects
Sending in an extension.
 If possible please use the
form
when sending extensions or comments.
 Ideally I would like to get enough terms for each sequence
to fill about three lines on the screen. Failing that even a
single extra term is always welcome.
 Please be sure to specify the sequence number
in any message.
 It is also a good idea to
give the first few terms as well as the terms before
that come before the new terms, to avoid
any confusion. It is very easy to type A045912 when
you mean A049512, and giving the first few terms
of the sequence helps to detect such errors!

What will be needed.

Some of these sequences can be calculated from the
formula, recurrence or generating function
given in the description.

Other sequences will require going to a library, to look up
the formula or recurrence given in the references
for the sequence (sometimes a reference will explicitly
list more terms, which the person who contributed the sequence
did not copy down).

Some sequences will require that you write a program to work them out
 for instance to count the structures of a certain kind.

Some of the sequences will be very hard to extend.
On the other hand there's more glory in extending them.
 All contributions will be acknowledged.
Computer programs.
If you can generate the sequence with a few lines
of code in one of the standard languages,
please send the program too. I am trying
to give computer code to generate sequences
whenever possible.
Updates.

The database is usually updated every few days, often
every day, so if you are working on a sequence for a while,
it is a good idea to recheck it to make sure no one
else has extended it. This file is automatically updated
with the main table.
 Please send email to
njas@research.att.com
if there is a sequence on the above list that should
not be there  for example if there are already enough terms to
fill three lines, if no more terms exist in the sequence,
or if the next term is more than 10^80.
Other problems.
See if you can improve any of the known lower bounds
on
constant weight codes.
Many of them are extremely weak!
