code: public static PermutationChromosome<Integer>
  	ofInteger(final IntRange range, final int length) {
  		return of(
  			range.stream()
  				.boxed()
  				.collect(ISeq.toISeq()),
  			length
  		);
  	}
docs: Create an integer permutation chromosome with the given range and length
  
  @since 3.4
  
  @param range the value range
  @param length the chromosome length
  @return a new integer permutation chromosome
  @throws NullPointerException if the given {@code range} is {@code null}
  @throws IllegalArgumentException if
  {@code range.getMax() - range.getMin() < length},
  {@code length <= 0} or
  {@code (range.getMax() - range.getMin())*length} will cause an
  integer overflow.