Genetic Programming with simple loops

A kind of loop function LoopN in Genetic Programming (GP) is proposed. Different from other forms of loop function, such as While-Do and Repeat-Until, LoopN takes only one argument as its loop body and makes its loop body simply runN times, so infinite loops will never happen. The problem of how to avoid too many layers of loops in Genetic Programming is also solved. The advantage of LoopN in GP is shown by the computational results in solving the mower problem.