In Genesis 4:
17 And Cain knew his wife; and she conceived, and bare Enoch: and he builded a city, and called the name of the city, after the name of his son, Enoch
18 And unto Enoch was born Irad
2: and Irad begat Mehujael
Mehujael begat Methusael
4: and Methusael begat Lamech
19 And Lamech took unto him two wives: the name of the one was Adah, and the name of the other Zillah.
20 And Adah bare Jabal
6: he was the father of such as dwell in tents, and of such as have cattle. 21 And his brother's name was Jubal
6: he was the father of all such as handle the harp and organ.
22 And Zillah, she also bare Tubalcain
6, an instructer of every artificer in brass and iron: and the sister of Tubalcain was Naamah.
As to the lineage of Seth;
25 And Adam knew his wife again; and she bare a son, and called his name Seth: For God, said she, hath appointed me another seed instead of Abel, whom Cain slew. 26 And to Seth, to him also there was born a son; and he called his name Enos: then began men to call upon the name of the LORD
6 And Seth lived an hundred and five years, and begat Enos
7 And Seth lived after he begat Enos eight hundred and seven years, and begat sons and daughters:
8 And all the days of Seth were nine hundred and twelve years: and he died.
9 And Enos lived ninety years, and begat Cainan
10 And Enos lived after he begat Cainan eight hundred and fifteen years, and begat sons and daughters:
11 And all the days of Enos were nine hundred and five years: and he died.
12 And Cainan lived seventy years, and begat Mahalaleel
13 And Cainan lived after he begat Mahalaleel eight hundred and forty years, and begat sons and daughters:
14 And all the days of Cainan were nine hundred and ten years: and he died.
15 And Mahalaleel lived sixty and five years, and begat Jared
4:thirty years, and begat sons and daughters:
17 And all the days of Mahalaleel were eight hundred ninety and five years: and he died.
And so forth...
Is there a significance to this 'omission'?