They appear to be either Asiatic hybrids or possibly longiflorum-Asiatic hybrids. If you can detect some fragrance when in bloom, they may be the latter (the fragrance coming from the longiflorum (Easter lily) side).
If you purchased them under a cultivar name we might be able to confirm; otherwise there are probably thousands of similar lilies. The Dutch lily industry spits these out like you wouldn't believe. They can look alike but there may be slight differences in height, size of flower, color of pollen etc.
