oops.. it is 680670[B]66
[/B]MY MISTAKE

I randomly picked up 1000336, just because it was only at 86 digits in the DB, and was surprised to find that after adding ~4000 terms it terminated (actually it merged with 7596 a while before that). That's my first termination -- fun!

[QUOTE=bchaffin;234589]I randomly picked up 1000336, just because it was only at 86 digits in the DB, and was surprised to find that after adding ~4000 terms it terminated (actually it merged with 7596 a while before that). That's my first termination -- fun![/QUOTE]

Congrats, I've added it to the Sequence terminations thread.

[URL="http://factordb.com/sequences.php?se=1&eff=2&aq=309480&action=last20"]309480[/URL] acquired the downdriver at height 128.

[URL="http://www.factordb.com/sequences.php?se=1&eff=2&aq=147192&action=range&fr=4740&to=4750"]147192[/URL] acquired a downdriver at height 140.

(Last time I had a downdriver at height 140, the downdriver run was something like 5 iterations, so I am not very excited. :no:)

[QUOTE=Batalov;235158][URL="http://www.factordb.com/sequences.php?se=1&eff=2&aq=147192&action=range&fr=4740&to=4750"]147192[/URL] acquired a downdriver at height 140.

(Last time I had a downdriver at height 140, the downdriver run was something like 5 iterations, so I am not very excited. :no:)[/QUOTE]Hey, keep the faith, man, maybe this time will work out better....

What was the other one? Clifford has you marked down with 138 on this sequence in Febrary of this year.

Right, now I remembered: must have been the [URL="http://mersenneforum.org/showpost.php?p=205308&postcount=555"]same one[/URL].

Well, at least it is now higher than 138 (which I though was also a 140). I am helping it now with msieve_GPU (on a RMA-swapped card; serves as a test, too).

[QUOTE=Batalov;235158](Last time I had a downdriver at height 140, the downdriver run was something like 5 iterations, so I am not very excited. :no:)[/QUOTE]

If I'm not mistaken, you have reason to be excited, because you can expect this one to last much longer. For the downdriver to break, the line must be 2*p with p=1 mod 4. So the chances of it breaking on any given line should be about the chance of the cofactor being prime and 1 mod 4. The chance of a random 140-digit number being prime is about 1/log(10^140), but it's odd which doubles the chance of being prime, but it must be 1 mod 4 which halves it back to 1/log(10^140). log(10^140) is about 332. By 130 digits, this is down to about 300. From very rough, in-my-head calculations, (and dependent on how much the sequence goes down - or up - during the downdriver run) I'd say there's only a 50% chance that it will stop within 200 indexes. It becomes more likely to break as it gets smaller and smaller.

68067066 is at i5397 114 digits, 2*11 (downdriver)

[URL="http://factordb.com/sequences.php?se=1&eff=2&aq=850956&action=last20&fr=0&to=100"]850956[/URL] is riding the second downdriver after the top of 126 digits. Fingers crossed.

[URL="http://factordb.com/sequences.php?se=1&aq=789816"]789816[/URL] just acquired the downdriver at a height of 104! (i1201) :fusion: Currently height 103, i1205, finishing a c91 GNFS.