A heptomino (or 7-omino or septomino) is a polyomino of order 7; that is, a polygon in the plane made of 7 equal-sized squares connected edge to edge.[1] The name of this type of figure is formed with the prefix hept(a)-. When rotations and reflections are not considered to be distinct shapes, there are 108 different free heptominoes. When reflections are considered distinct, there are 196 one-sided heptominoes. When rotations are also considered distinct, there are 760 fixed heptominoes.[2][3]
- ^ Golomb, Solomon W. (1994). Polyominoes (2nd ed.). Princeton, New Jersey: Princeton University Press. ISBN 0-691-02444-8.
- ^ Weisstein, Eric W. "Heptomino". From MathWorld – A Wolfram Web Resource. Retrieved 2008-07-22.
- ^ Redelmeier, D. Hugh (1981). "Counting polyominoes: yet another attack". Discrete Mathematics. 36 (2): 191–203. doi:10.1016/0012-365X(81)90237-5.