letter sequences

[hellsbells]

letter sequence is HI IH HJ JH and the next two, which is the answer are FI IF but no idea why?

anyone explain this one?

[Complete Novice]

Hellsbells, I posted the same sequence on November 18 last year as I was completely stumped. I found it on the Pates example papers from their website. You will see from the replies I got that no one managed to figure it out. Perhaps it was an error? Certainly I haven't come across anything as tricky as that since.

Good luck!

CN