I have just found 3rd known (the largest known) prime 18-tuplet:

Prime 18-tuplet

4530085223434265844952597 + d,

d = 0, 4, 10, 12, 16, 22, 24, 30, 36, 40, 42, 46, 52, 54, 60, 64, 66, 70

(25 digits, Dec 14, 2008, Jaroslaw Wroblewski)

The search has started on December 4. I am using up to 60 64-bit

computers in students labs at Mathematical Institute of Wroclaw

University (sometimes fewer if the are down or used by students).

I estimate that I have deserved to find about 0.5-0.6 of an 18-tuplet

by now, so I was a bit lucky. I will continue the search in hope for

more 18-tuplets or for a miracle (19-tuplet).

Jarek