# OEIS

9 Hacker News commenters recommended OEIS and 1 criticized it, November 2025 to November 2026. It was recommended in 6 of 13 months.

**Verdict:** Free online database of integer sequences; people use it to look up a sequence from its first few terms and to find background information on it.

## Why people recommend it

- Look up sequences from first few terms (2 comments): "I've solved a lot of otherwise seemingly quite hard problems by numerically/brute-force finding the first few terms then asking OEIS" ([source](https://news.ycombinator.com/item?id=48639224)) ""Compute the first few terms and plug into OEIS" is very high on the reward:effort scale" ([source](https://news.ycombinator.com/item?id=48635344))
- Shows whether a sequence already exists (2 comments): "Before you pick a number check if that sequence exists and someone might share your interest" ([source](https://news.ycombinator.com/item?id=47962093)) "searching that sequence on OEIS should give a lot of good information" ([source](https://news.ycombinator.com/item?id=48819549))
- Useful for maths reading and practice (2 comments): "the OEIS is an excellent resource for both readinh and sharpening one's amateur teeth" ([source](https://news.ycombinator.com/item?id=47124117)) "The encyclopedia of integer sequences can be quite useful" ([source](https://news.ycombinator.com/item?id=48819607))

## Alternatives hackers recommend

- [Sheldon Brown's Bicycle Technical Info](https://hackerapproved.com/p/sheldon-brown-s-bicycle-technical-info.md): 49 recommend
- [Animated Knots by Grog](https://hackerapproved.com/p/animated-knots.md): 14 recommend
- [Ian's Shoelace Site](https://hackerapproved.com/p/ian-s-shoelace-site.md): 10 recommend
- [RF Cafe](https://hackerapproved.com/p/rf-cafe.md): 9 recommend
- [Snopes](https://hackerapproved.com/p/snopes.md): 8 recommend

## Where to get it

- [Visit the official site](https://oeis.org/)

## Cite as

Hacker Approved, "OEIS", https://hackerapproved.com/p/oeis/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).