The next letter will be C.
To find this you must first take and write out the alphabet and assign a number to each letter. So A = 1, B = 2 and C = 3. After you have finished this then LONLPIRFT becomes 12,15,14,12,16,9,18,6,20. Now we need to find the pattern. If you count up the letters their are 9. So you either have 4 pairs with a final pair that is incomplete or you have a pattern that is associated with 3 sets of 3. If you try the 3 sets of 3 first you do not come up with a pattern that is recognizable so you then look at the first set of numbers in a pair. 12 and 15, if you add these two together they become 27. Then the second pair is 14 and 12. If you add these toghether they become 26. I think we found the pattern that is decreasing by 1. So the last pattern should have a sum that equals 23. Simple algebra tells us that number is 3 wich is refferenced to C.
So the pattern is LONLPIRFTC
12+15 = 27
14+12 = 26
16+9 = 25
18+6 = 24
20+X = 23
what is the next letter e h l q
X
S
c
Q
The next (and last) letter is C. Just as a countdown counts backwards, this series is "countdown" spelled backwards.
c is next
y
S
T
It's the letter D of course! Haven't you heard of Jason D?!
R