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MathNet 2007-part-03 — 185 problems (EN–VI) Question 175

Math Olympiad Vault · MathNet 2007-part-03 — 185 problems (EN–VI)

Question 175

An *animal* with $n$ cells is a connected figure consisting of $n$ equal-sized square cells. Animals are also called *polyominoes*. They can be defined inductively. Two cells are *adjacent* if they share a complete edge. A single cell is an animal, and given an animal with $n$ cells, one with $n+1$ cells is obtained by adjoining a new cell by making it adjacent to one or more existing cells.

A dinosaur is an animal with at least $2007$ cells. It is said to be primitive if its cells cannot be partitioned into two or more dinosaurs. Find with proof the maximum number of cells in a primitive dinosaur.

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