I think I recall this website at one point existing at a domain from Bell Labs. I came across it almost 8 years ago searching on Google for a particular number sequence I came across in some research. The website is fascinating and I found myself looking at sequences for hours, amazed by all of the different ones that had been posted. This website is definitely one of the great hidden gems on the Internet.
Sloane kept his collection first on punched cards, then in a “handbook”—A Handbook of Integer Sequences, published in 1973, with the copyright held by Bell Telephone Laboratories, where he started working in 1968. In 1995 he launched an automated email lookup service called Superseeker, whereby the curious submitted sequence queries and the database replied with answers. In 1996 he opened up his repository for public browsing at oeis.org. With the lab’s blessing, Sloane put it up on the research division’s website.
In college I attended a great talk by Herb Wilf that was his foolproof plan for writing a combinatorics paper: Basically, find two sequences on the OEIS that look unrelated and prove a relationship between them.
A few weeks ago I was working through the Google Foobar challenges and came upon a problem where I had to calculate a certain function. I could calculate the first few values of the function by hand, but was having trouble coming up with a general expression so I plugged the sequence into OEIS. I was pleasantly surprised to find that not only did OEIS have it, but it was actually the very first sequence in there! (Confusingly it is numbered A000435, not A000001.) OEIS gave me the general expression and from there I could solve the problem!
Too many times I've 'solved' a Project Euler problem like this:
1. Write a program to solve the problem inefficiently.
2. Look up the sequence F(1), F(2), F(3) ... at oeis.org
