Too many similar sequences

hv at crypt.org hv at crypt.org
Fri Apr 8 05:14:27 CEST 2005


As part of my investigation into A33179, I wanted to find the sequence
of partitions of n. So I calculated a few values by hand, whacked them
into the advanced look-up page (my usual jump-off point), and waded
through the 30-odd results looking for the one I wanted.

No joy, so I calculated more terms - I ended up having to calculate
the first 9 terms (1, 2, 3, 5, 7, 11, 15, 22, 30) before A41 appeared
at all in the search results.

It appears to be getting pushed out of the way by a lot of what I'd
consider fairly trivial variations - they are mostly variant partition
functions with minor restrictions - so I wonder if there is any way
that the "core" sequences could be preferentially shown in such
situations?

I appreciate that it may be difficult to reconcile this with the need
to keep the database search as fast as possible: I suspect that the
sequences are ordered (somehow) in numerical order, and that this
particular search was problematic because all the variants tend to
add a restriction so that - after enough terms - the variant starts
to take lower values than A41, and so gets sorted earlier than A41.

Whatever the cause, I suspect this sort of problem will become more
common as the database continues to grow.

It might also be useful to consider automatic linking of a selected
set of key words and phrases - when searching with the first 8 terms
of A41, none of the first 25 results returned include a reference to
A41 even though many of them had "partition" as a part of the
definition. I imagine most of the core sequence have short names
that it might be useful to link in this manner - even "integer"
might not be excessive.

Hugo





More information about the SeqFan mailing list