Originated, June 29, 1998. Revised March 14, 2003, November 7, 2003.
1. I know very little about number things in the OT, and what I do know is decreasing (e.g., I am losing confidence that all/many/most of them were MEANT by the author to be taken as real 'numbers'...some cases seem to be obvious symbolic values, semi-puns, pedagogical devices, memory aids, etc.).
2. Genealogies are especially problematic, IMO, since the numbers in them had ZERO importance to their social function (i.e., to situate an individual in an social context)--numbers meant/contributed NOTHING to this task, and are accordingly 'window dressing' and/or a way to indicate SOME THING ELSE. What this 'something else' is, in an ancient context, both variable and unclear to me.
3. The LXX "bails us out" several times in OT numerical problems/contradictions, so, as a source it has a high--but uneven--credibility with me for such things.
4. I haven't studied this, but if I had to, the approach I would START WITH would be to build a comparative table of four (maybe five or six) columns, with one row for each number in Gen 1-11 (not just genealogy numbers--patterns in other numbers might reveal some pattern of number 'meaning' or literary usage).
The rows would consist of the numbers in the different versions:
(1) The MT (obviously, but you would need to check the Text Apparatus for juicy variants),
(2) The LXX (obviously),
(3) The Dead Sea Scrolls (representing our OLDEST real mss of the Hebrew bible, of course. I would start with the work by Abegg, Flint, Ulrich --"The Dead Sea Scrolls Bible", and if one of the numbers they give look juicy, you could drill down);
(4) the Peshitta (of possible value),
(5) the Targums (late, but still BEFORE the MT in many cases); and
(6) parallels from the OT Pseudepigrapha and Apoc.: the category/genre known as "Retold Bible" are paraphrases/expansions of the early narratives (esp. Patriarchal), so you might find some interesting stuff in there. Since many/most of these are pre-MT (and some anti-MT...smile), they might could be of importance to your quest. [You could also check the rabbinics--Ginzberg's Legends of the Jews probably has all the alternate dates/ages/lengths listed in his work...there might be some variants in there.]
That's all I can suggest, since the next step would depend upon what patterns were detectable in the columns, of course...but it would be a fascinating subject!
"...[God] has put eternity into the hearts of men, yet so that no man can find out what God has done from the beginning to the end."
"So when they [the disciples] had come together, they asked him, 'Lord, will you at this time restore the kingdom to Israel?' Jesus said to them, 'It is not for you to know times (chronos) or seasons (kairos) which the Father has fixed by his own authority.'" (Acts 1:6-7)
First of all you must understand this, that scoffers will come in the last days with scoffing, following their own passions and saying, "Where is the promise of his coming? Forever since the fathers fell asleep, all things have continued as they were from the beginning of creation." They deliberately ignore this fact, that by the word of God heavens existed long ago, and an earth formed out of water and by means of water, through which the world that then existed was deluged with water and perished. But by the same word the heavens and earth that now exist have been stored up for fire, being kept until the day of judgment and destruction of ungodly men. But do not ignore this one fact, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day.
The Lord is not slow about his promise as some count slowness, but is forbearing toward you, not wishing that any should perish, but that all should reach repentance. But the day of the Lord will come like a thief, and then the heavens will pass away with a loud noise, and the elements will be dissolved with fire, and the earth and the works that are upon it will be burned up. Since all these things are thus to be dissolved, what sort of persons ought you to be in lives of holiness and godliness, waiting for and hastening the coming of the day of God, because of which the heavens will be kindled and dissolved, and the elements will melt with fire! But according to his promise we wait for new heavens and a new earth in which righteousness dwells.
Therefore, beloved, since you wait for these, be zealous to be found by him without spot or blemish, and at peace. And count the forbearance of our Lord as salvation. So also our beloved brother Paul wrote to you according to the wisdom given him, speaking of this as he does in all his letters. There are some things in them hard to understand, which the ignorant and unstable twist to their own destruction, as they do the other scriptures.
You therefore, beloved, knowing this beforehand, beware lest you be carried away with the error of lawless men and lose your own stability. But grow in the grace and knowledge of our Lord and Savior Jesus Christ. To him be the glory both now and to the day of eternity. Amen.