There is a huge (maybe infinite) number of twin primes, like (11,13), but only one triplet with d=2, i.e. (3,5,7).
However, one can get longer arithmetic series with other values of d.

Please list all the increasing arithmetic series such that:
a. They consist of at least 5 prime members.
b. Each number is under 100.

Example: 5,11,17,23,29. (d=6)

(In reply to expanding (spoiler included) by Charlie)

I see upon expanding the search even farther, that the 9-member series is really the start of a 10-member series:

 199  409  619  829  1039  1249  1459  1669  1879  2089

Posted by Charlie on 2011-11-17 12:57:52