From Rob
A (1) The book of the generation of Jesus Christ,
B (1) the son of David,
C (1) the son of Abraham.
C’ (17) So all the generations from Abraham
B’ (17) to David are fourteen generations; and from David until the carrying away into Babylon are fourteen generations;
A’ (17) and from the carrying away into Babylon unto Christ are fourteen generations.
This pattern has been called “a chiastic inclusio”