It looks like it is quite old, but I found the Combinatorial Object Server for the first time this week and I thought I’d share it with my readers. I was looking for irreducible polynomials with binary coefficients (don’t ask why) and I found that this server can generate them on the fly for you! A beautiful application of the web.
Here are some things it can do:
- Permutations and their restrictions
- Subsets or Combinations
- Permutations or Combinations of a Multiset
- Set Partitions
- Numerical Partitions and relatives
- Binary, rooted, free and other trees
- Necklaces, Lyndon words, DeBruijn Sequences
- Irreducible and Primitive Polynomials over GF(2) to GF(5)
This reminds me a bit of the famous Plouffe’s inverter which, given a floating point number, will give you a matching mathematical constant.