TL; DR; Where can I publish proofs that are not groundbreaking nor profound?
I recently found an integer sequence in the OEIS. Okay, the OEIS only contains integer sequences, so nothing new so far. However, the entry for this sequence mentioned an upper bound that I thought could be improved upon. The entry also mentioned a couple of properties for which I could find no proof in the referenced articles/literature.
The proofs for all of these properties, including the upper bound, are not trivial, but also not very difficult, I'd say first year undergrad.
I would like to expand the entry with the improved upper bound, but since I do not trust myself to be mistake-free and I do not expect others to trust me, I think the entry should contain references to proofs for every fact that it mentions, since it is very important these properties are correct.
My question is therefore: where can I publish/put/leave such proofs, in such a way that people who use the OEIS can read them as well (in order to verify it for themselves)? It is by no means groundbreaking work, nor very important, so I don't think any journal (or person reading a journal) would be interested in it, but as scientists and mathematicians, it is always important to give proofs for the claims we do. The only place that I could think of for such a publication is arXiv.org, but I am not sure whether that would be appopriate or not.