"A Handbook of Integer Sequences" Fifty Years Later

TL;DR

This paper reviews the fifty-year evolution of the integer sequence database from the original handbook to the modern OEIS, highlighting its growth, impact, and role in mathematical discovery.

Contribution

It documents the development and significance of the OEIS, illustrating how it transformed the accessibility and study of integer sequences over fifty years.

Findings

OEIS contains 360,000 entries

OEIS receives a million visits daily

OEIS has been cited 10,000 times

Abstract

Until 1973 there was no database of integer sequences. Someone coming across the sequence 1, 2, 4, 9, 21, 51, 127,... would have had no way of discovering that it had been studied since 1870 (today these are called the Motzkin numbers, and form entry A001006 in the database). Everything changed in 1973 with the publication of "A Handbook of Integer Sequences", which listed 2372 entries. This report describes the fifty-year evolution of the database from the "Handbook" to its present form as "The On-Line Encyclopedia of Integer Sequences" (or OEIS), which contains 360,000 entries, receives a million visits a day, and has been cited 10,000 times, often with a comment saying "discovered thanks to the OEIS".