The On-Line Encyclopedia of Integer Sequences: what it is & sites like it

The On-Line Encyclopedia of Integer Sequences is a database of sequences of whole numbers, from the Fibonacci numbers to obscure ones. The trick is that you search by the numbers themselves. Type a few terms, and the site tells you what sequence they might belong to.

That makes it a lovely tool for mathematicians and a fun toy for everyone else. Enter your birthday digits or a number series you invented and see what turns up. Entries carry formulas, references and comments.

It was founded by Neil Sloane. The interface is plain but dense, and we have not confirmed how well it works on phones. It is a numerical rabbit hole for maths fans. Related: /site/explained-visually and /category/oddly-educational. Plan on plenty of time, since it is a genuine rabbit hole.

Tips for getting the most out of it

Enter a handful of terms, separated by commas.
Try your own made-up sequence.
Read the comments on an entry.

Questions about The On-Line Encyclopedia of Integer Sequences

What is the OEIS?

The OEIS is an online database of integer sequences that you can search by entering a few terms. Plan on plenty of time, since it is a genuine rabbit hole. We have not confirmed how well it works on phones. You can find it at oeis.org, and we check the link daily.

Who founded the OEIS?

It was founded by Neil Sloane. Plan on plenty of time, since it is a genuine rabbit hole. We have not confirmed how well it works on phones. You can find it at oeis.org, and we check the link daily.