I see that many people have tried to solve this unsuccessfully. I thought it would be good to post it again, this time in the original form in which it appears in the source, just in case there is some significant information there. 4, 8, 16, 26, 41, 57, 79, 104, 138, 184, 241, ? a = 298 z = 323 A = 324 Z = 349 The only significant thing I see there is that