These two enigmas borrow from the other.
The first is not uniquely concerned with letters
and the second is not uniquely concerned with numbers.
We do not want to give you too much help with either one.

Start with these letters

The original puzzle
Continue trhe following sequence by adding the next three letters :

O, T, T, F, F, S, S, . . .

The Solution
We hope that you do not need one, and, above all, that you did not count on us.

Move on to numbers

The original puzzle
Continue trhe following sequence by adding the next row of numbers :

1
1 1
2 1
1 2 1 1
1 1 1 2 2 1
3 1 2 2 1 1
? ? ? ? ? ? ? ?

The Solution
There are 2 procedures here -
         Each line describes the preceding line and
         adjectives become nouns in the following line.
                   The first line contains a noun (like "apple").
                   The second line sees a specific number (numerical adjective) of the noun in the first line,
                             "one apple".
                   The third line sees two nouns in the second line,
                             "two apples".
                   The fourth line sees a new noun (like "pear") in the third line,
                             "one pear, one apple".
                   The fifth line again sees nothing but nouns in the fourth line,
                             "one apple, one pear, two apples".
                   The sixth line again sees nothing but nouns in the fifth line,
                             "three apples, two pears, one apple".
                   What does the seventh line see ?