Matthew 1:17 states there were 42 generations from Abraham until Jesus, what do these 42 generations mean?

It means that it's irrefutable proof that Christianity is the real Answer to the Ultimate Question of Life, the Universe, and Everything.

6 times 7. Jesus is the first of the 7 x 7.

They are the begats.

And Peeleg begat Bakrub, and Bakrub begat Jehotfat, and Jehotfat begat Crapoliah and so forth...up to and including Jesus.

Numbers do have meaning in the Bible. 42 divided by 12, the number of Israel, yields 3 ½. This is a prophetic number in both Daniel chapter 12 and in Revelation. See Daniel 12:1-13 (focus on verse 7 which adds up to 3 ½ ). 3 ½ is half of 7. It is an imperfect number. Note: both St. Jerome and Pope St Gregory the Great wrote extensively about and gematria its significance in Scripture. Sir Isaac Newton wrote more about gematria and numbers in Scripture than he did about the theory of gravity.