Problem: You have discovered a new plant species in your garden. The pattern on the leaves is determined by a single gene with 5 different alleles. Each allele produces a different pattern, but one allele is recessive to the other 4 alleles, and another allele is dominant to the other 4 alleles. Besides, 3 alleles are codominant with each other. (Therefore, 1 dominant, 1 recessive, and 3 codominant alleles exist.)
There is/are phenotype(s) (leaf pattern) that could be represented by only a single genotype. What is the number of such phenotypes (leaf patterns)?