E
One Two Three Four Five Six Seven Eight
The last two in that collection are s and s. The next two are e and n.
E its the first letter of the number sequence one, two three four five six seven Eight
I means: O=1 T=2 T=3 F=4 F=5 S=6 S=7 E=8 and Then N is the answer because its for 9.
There are the initial letters of numbers 1 to 7 # One # Two # Three # Four # Five # Six # Seven so the next 3 letters represent Eight, Nine and Ten
Actually this is a riddle. O T T F F S S is a pattern. The next letter will be E. Each letter stand for the beginning letter of how the number is spelled. One Two Three Four Five .. and so on..
This sequence is formed from the first letters of numbers starting from one and counting upwards.Basically, it goes:OneTwoThreeFourFiveSixand so on.The sequence you gave goes up to Twenty-oneSo the next few terms would beTwenty-twoTwenty-threeTwenty-four...Giving TTTTTTTT....