Klarner, D. A.; Rivest, R. L. A procedure for improving the upper bound for the number of \(n\)-ominoes. (English) Zbl 0261.05113 Can. J. Math. 25, 585-602 (1973). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 45 Documents MSC: 05C30 Enumeration in graph theory 05C25 Graphs and abstract algebra (groups, rings, fields, etc.) 05C05 Trees PDF BibTeX XML Cite \textit{D. A. Klarner} and \textit{R. L. Rivest}, Can. J. Math. 25, 585--602 (1973; Zbl 0261.05113) Full Text: DOI Online Encyclopedia of Integer Sequences: Number of free polyominoes (or square animals) with n cells. Number of fixed polyominoes with n cells.