The On-Line Encyclopedia of Integer Sequences (OEIS), also cited simply as Sloane's, is an extensive searchable database of integer sequences, freely available on the Web.
M. Becker, H. Mewes, A. Hotho, D. Dimitrov, F. Lemmerich, and M. Strohmaier. International Conference Companion on World Wide Web, page 17--18. Republic and Canton of Geneva, Switzerland, International World Wide Web Conferences Steering Committee, (2016)